All Problems
Output a string to the console
Write the string
"Hello World!" to STDOUT
perl
print "Hello World!\n"
erlang
io:format("Hello, World!~n").
csharp
System.Console.WriteLine("Hello World!")
Retrieve a string containing ampersands from the variables in a url
My PHP script first does a query to obtain customer info for a form. The form has first name and last name fields among others. The customer has put entries such as
The script variable for first name $_REQUEST
I have tried various functions like urldecode but all to no avail. I even tried encoding the url before the view screen is painted so that the url looks like
Of course this fails for the same reasons. What is a better approach?
"Ron & Jean" in the first name field in the database. Then the edit form script is called with variables such as
"http://myserver.com/custinfo/edit.php?mode=view&fname=Ron & Jean&lname=Smith".
The script variable for first name $_REQUEST
['firstname'] never gets beyond the "Ron" value because of the ampersand in the data.
I have tried various functions like urldecode but all to no avail. I even tried encoding the url before the view screen is painted so that the url looks like
"http://myserver/custinfo/edit.php?mode=view&fname="Ronxxnbsp;xxamp;xxnbsp;Jean"&lname=SMITH". (sorry I had to add the xx to replace the ampersand or it didn't display meaningful url contents the browser sees.)
Of course this fails for the same reasons. What is a better approach?
perl
print "http://myserver.com/custinfo/edit.php"
."?fname=".urlenc('Ron & Jean')
."&lname=".urlenc('Smith');
sub urlenc{my($s)=@_;$s=~s/([^A-Za-z0-9])/sprintf("%%%02X",ord($1))/seg;$s}
."?fname=".urlenc('Ron & Jean')
."&lname=".urlenc('Smith');
sub urlenc{my($s)=@_;$s=~s/([^A-Za-z0-9])/sprintf("%%%02X",ord($1))/seg;$s}
erlang
% encode ampersand in your string using %XX where XX is hex code for ampersand
% optionally encode spaces for completeness sake to keep URL solid
URL = "http://myserver.com/custinfo/edit.php?mode=view&fname=Ron%20%26%20Jean&lname=Smith",
{_, Query} = string:tokens(URL, "?"),
KeyValuePairs = string:tokens(Query, "&"),...
% optionally encode spaces for completeness sake to keep URL solid
URL = "http://myserver.com/custinfo/edit.php?mode=view&fname=Ron%20%26%20Jean&lname=Smith",
{_, Query} = string:tokens(URL, "?"),
KeyValuePairs = string:tokens(Query, "&"),...
string-wrap
Wrap the string
Expected output:
> The quick brown fox jumps over the lazy dog. The quick brown fox jumps over t
> he lazy dog. The quick brown fox jumps over the lazy dog. The quick brown fox
> jumps over the lazy dog. The quick brown fox jumps over the lazy dog. The qui
> ck brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy
> dog. The quick brown fox jumps over the lazy dog. The quick brown fox jumps o
> ver the lazy dog. The quick brown fox jumps over the lazy dog.
"The quick brown fox jumps over the lazy dog. " repeated ten times to a max width of 78 chars, starting each line with "> "
Expected output:
> The quick brown fox jumps over the lazy dog. The quick brown fox jumps over t
> he lazy dog. The quick brown fox jumps over the lazy dog. The quick brown fox
> jumps over the lazy dog. The quick brown fox jumps over the lazy dog. The qui
> ck brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy
> dog. The quick brown fox jumps over the lazy dog. The quick brown fox jumps o
> ver the lazy dog. The quick brown fox jumps over the lazy dog.
erlang
wrapper(String, Times, Length) ->
StrList = lists:reverse(formatter(string:copies(String, Times), Length, [])),
lists:foreach(fun(Str) -> io:format("~p~n", [Str]) end, StrList).
formatter([], _Length, Acc) -> Acc;
formatter(String, Length, Acc) when length(String) > Length - 1->
{Head, Tail} = lists:split(Length - 1, String),
formatter(string:strip(Tail), Length, [[$>, $ | Head] | Acc]);
formatter(String, Length, Acc) ->
formatter([], Length, [[$>, $ | String] | Acc]).
StrList = lists:reverse(formatter(string:copies(String, Times), Length, [])),
lists:foreach(fun(Str) -> io:format("~p~n", [Str]) end, StrList).
formatter([], _Length, Acc) -> Acc;
formatter(String, Length, Acc) when length(String) > Length - 1->
{Head, Tail} = lists:split(Length - 1, String),
formatter(string:strip(Tail), Length, [[$>, $ | Head] | Acc]);
formatter(String, Length, Acc) ->
formatter([], Length, [[$>, $ | String] | Acc]).
Define a string containing special characters
Define the literal string
"\#{'}${"}/"
perl
$special = '\#{\'}${"}/';
$special = q(\#{'}${"}/);
erlang
Special = "\\#{'}\${\"}/",
csharp
string verbatim = @"\#{'}${""""}/";
string cStyle = "\\#{'}${\"\"}/";
string cStyle = "\\#{'}${\"\"}/";
Define a multiline string
Define the string:
"This
Is
A
Multiline
String"
perl
$text = 'This
Is
A
Multiline
String';
Is
A
Multiline
String';
$text = <<EOF;
This
Is
A
Multiline
String
EOF
This
Is
A
Multiline
String
EOF
erlang
Text = "This\nIs\nA\nMultiline\nString",
csharp
string output = "This\nIs\nA\nMultiline\nString";
string output = @"This
Is
A
Multiline
String";
Is
A
Multiline
String";
Define a string containing variables and expressions
Given variables a=3 and b=4 output
"3+4=7"
perl
print "$a+$b=${\($a+$b)}\n";
sprintf("%d+%d=%d", $a, $b, $a + $b);
print $a, '+', $b, '=', $a + $b;
erlang
A = 3, B = 4,
io:format("~B+~B=~B~n", [A, B, (A+B)]).
io:format("~B+~B=~B~n", [A, B, (A+B)]).
csharp
int a = 3;
int b = 4;
Console.WriteLine("{0}+{1}={2}", a,b,a+b);
int b = 4;
Console.WriteLine("{0}+{1}={2}", a,b,a+b);
Reverse the characters in a string
Given the string
"reverse me", produce the string "em esrever"
perl
$_ = reverse "reverse me"; print
erlang
Reversed = lists:reverse("reverse me"),
Reversed = revchars("reverse me"),
csharp
var str = "reverse me";
Console.WriteLine(new String(str.Reverse().ToArray()));
Console.WriteLine(new String(str.Reverse().ToArray()));
Reverse the words in a string
Given the string
"This is a end, my only friend!", produce the string "friend! only my end, the is This"
perl
$reversed = join ' ', reverse split / /, $text;
erlang
Reversed = string:join(lists:reverse(string:tokens("This is the end, my only friend!", " ")), " "),
csharp
var str = "This is a end, my only friend!";
str = String.Join(" ", str.Split().Reverse().ToArray());
Console.WriteLine(str);
str = String.Join(" ", str.Split().Reverse().ToArray());
Console.WriteLine(str);
Text wrapping
Wrap the string
> The quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog.
"The quick brown fox jumps over the lazy dog. " repeated ten times to a max width of 78 chars, starting each line with "> ", yielding this result:
> The quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog.
perl
use Text::Wrap;
$text = "The quick brown fox jumps over the lazy dog. ";
$Text::Wrap::columns = 73;
print wrap('> ', '> ', $text x 10);
$text = "The quick brown fox jumps over the lazy dog. ";
$Text::Wrap::columns = 73;
print wrap('> ', '> ', $text x 10);
$_ = "The quick brown fox jumps over the lazy dog. " x 10;
s/(.{0,70}) /> $1\n/g;
print;
s/(.{0,70}) /> $1\n/g;
print;
erlang
TextWrap = textwrap(string:copies(Input, 10), 73 - length(Prefix)),
lists:foreach(fun (Line) -> io:format("~s~n", [string:concat(Prefix, Line)]) end, string:tokens(TextWrap, "\n")).
lists:foreach(fun (Line) -> io:format("~s~n", [string:concat(Prefix, Line)]) end, string:tokens(TextWrap, "\n")).
csharp
using System;
using System.Text;
using System.Linq; // used for Array.ToList() extension
public class TextWrapper {
/// <summary>
/// Wrap the given text to a given width.
/// </summary>
/// <param name="text">The text to be wrapped</param>
/// <param name="width">The maximum width of each line</param>
/// <param name="prefix">Begin each line with this prefix</param>
/// <returns>The wrapped text</returns>
public string Wrap(string text, int width, string prefix) {
var words = text.Split(' ').ToList();
var result = new StringBuilder(prefix);
width = width - prefix.Length;
prefix = "\n" + prefix;
int lineSize = 0;
foreach (var word in words) {
int wordLen = word.Length;
// Do we need to start a new line?
if ((lineSize + wordLen) > width) {
result.Remove(result.Length - 1, 1); // remove trailing space
lineSize = 0;
result.Append( prefix );
}
result.Append(word).Append(' ');
lineSize += wordLen + 1;
}
return result.ToString();
}
public static void Main() {
var prefix = "> ";
var sentence = "The quick brown fox jumps over the lazy dog. ";
var text = "";
for (int i = 0; i < 10; i++)
text += sentence;
// The description said lines of length 78, but
// the example was 72...
Console.WriteLine(new TextWrapper().Wrap(text, 72, prefix));
}
}
using System.Text;
using System.Linq; // used for Array.ToList() extension
public class TextWrapper {
/// <summary>
/// Wrap the given text to a given width.
/// </summary>
/// <param name="text">The text to be wrapped</param>
/// <param name="width">The maximum width of each line</param>
/// <param name="prefix">Begin each line with this prefix</param>
/// <returns>The wrapped text</returns>
public string Wrap(string text, int width, string prefix) {
var words = text.Split(' ').ToList();
var result = new StringBuilder(prefix);
width = width - prefix.Length;
prefix = "\n" + prefix;
int lineSize = 0;
foreach (var word in words) {
int wordLen = word.Length;
// Do we need to start a new line?
if ((lineSize + wordLen) > width) {
result.Remove(result.Length - 1, 1); // remove trailing space
lineSize = 0;
result.Append( prefix );
}
result.Append(word).Append(' ');
lineSize += wordLen + 1;
}
return result.ToString();
}
public static void Main() {
var prefix = "> ";
var sentence = "The quick brown fox jumps over the lazy dog. ";
var text = "";
for (int i = 0; i < 10; i++)
text += sentence;
// The description said lines of length 78, but
// the example was 72...
Console.WriteLine(new TextWrapper().Wrap(text, 72, prefix));
}
}
Remove leading and trailing whitespace from a string
Given the string
" hello " return the string "hello".
perl
my $string = " hello ";
$string =~ s{
\A\s* # Any number of spaces at the start of the string
(.+?) # Remember any number of characters until we reach
\s*\z # any number of spaces at the end of the string
}{
$1 # Leave the characters we remembered
}x;
$string =~ s{
\A\s* # Any number of spaces at the start of the string
(.+?) # Remember any number of characters until we reach
\s*\z # any number of spaces at the end of the string
}{
$1 # Leave the characters we remembered
}x;
my $string = " hello ";
$string =~ s{\A\s*}{};
$string =~ s{\s*\z}{};
$string =~ s{\A\s*}{};
$string =~ s{\s*\z}{};
#Modification History:
# 2009-MAR-17: GGARIEPY: [creation] (geoff.gariepy@gmail.com)
$string = " hello ";
$string =~ s/^\s+|\s+$//g; # All the action happens in one regex!
# Regex Notes:
# ^ - anchors to the beginning of the string
# $ - anchors to the end of the string
# g - causes regex to match as many times as possible
# | - logical OR
# 2009-MAR-17: GGARIEPY: [creation] (geoff.gariepy@gmail.com)
$string = " hello ";
$string =~ s/^\s+|\s+$//g; # All the action happens in one regex!
# Regex Notes:
# ^ - anchors to the beginning of the string
# $ - anchors to the end of the string
# g - causes regex to match as many times as possible
# | - logical OR
erlang
Trimmed = string:strip(S),
csharp
string str = " hello ";
str = str.Trim();
Console.WriteLine(str);
str = str.Trim();
Console.WriteLine(str);
Simple substitution cipher
Take a string and return the ROT13 and ROT47 (Check Wikipedia) version of the string.
For example:
String is: Hello World #123
ROT13 returns: Uryyb Jbeyq #123
ROT47 returns: w6==@ (@C=5 R`ab
For example:
String is: Hello World #123
ROT13 returns: Uryyb Jbeyq #123
ROT47 returns: w6==@ (@C=5 R`ab
perl
sub rot13 {
my $str = shift;
$str =~ tr/A-Za-z/N-ZA-Mn-za-m/;
return $str;
}
sub rot47 {
my $str = shift;
$str =~ tr/!-~/P-~!-O/;
return $str;
}
my $string = 'Hello World #123';
print "$string\n";
print rot13($string)."\n";
print rot47($string)."\n";
my $str = shift;
$str =~ tr/A-Za-z/N-ZA-Mn-za-m/;
return $str;
}
sub rot47 {
my $str = shift;
$str =~ tr/!-~/P-~!-O/;
return $str;
}
my $string = 'Hello World #123';
print "$string\n";
print rot13($string)."\n";
print rot47($string)."\n";
erlang
rot13(Str) ->
lists:map(fun(A) ->
if
A >= $A, A =< $Z -> ((A - $A + 13) rem 26) + $A;
A >= $a, A =< $z -> ((A - $a + 13) rem 26) + $a;
true -> A
end
end, Str).
rot47(Str) ->
lists:map(fun(A) ->
if
A >= $!, A =< $~ ->
((A - $! + 47) rem 94) + $!;
true -> A
end
end, Str).
lists:map(fun(A) ->
if
A >= $A, A =< $Z -> ((A - $A + 13) rem 26) + $A;
A >= $a, A =< $z -> ((A - $a + 13) rem 26) + $a;
true -> A
end
end, Str).
rot47(Str) ->
lists:map(fun(A) ->
if
A >= $!, A =< $~ ->
((A - $! + 47) rem 94) + $!;
true -> A
end
end, Str).
Make a string uppercase
Transform
"Space Monkey" into "SPACE MONKEY"
perl
print uc "Space Monkey"
erlang
io:format("~s~n", [string:to_upper("Space Monkey")]).
csharp
string output = "Space Monkey"
System.Console.WriteLine(output.ToUpper())
System.Console.WriteLine(output.ToUpper())
Make a string lowercase
Transform
"Caps ARE overRated" into "caps are overrated"
perl
print lc "Caps ARE overRated"
erlang
io:format("~s~n", [string:to_lower("Caps ARE overRated")]).
csharp
string str = "Caps ARE overRated";
str = str.ToLower() ;
Console.WriteLine(str);
str = str.ToLower() ;
Console.WriteLine(str);
Capitalise the first letter of each word
Transform
"man OF stEEL" into "Man Of Steel"
perl
$text =~ s/(\w+)/\u\L$1/g;
erlang
Caps = string:join(lists:map(fun(S) -> to_caps(S) end, string:tokens("man OF stEEL", " ")), " "),
csharp
System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo.ToTitleCase("man OF stEEL".ToLowerInvariant());
Find the distance between two points
perl
use Math::Complex;
$a = Math::Complex->make(0, 3);
$b = Math::Complex->make(4, 0);
$distance = abs($a - $b);
$a = Math::Complex->make(0, 3);
$b = Math::Complex->make(4, 0);
$distance = abs($a - $b);
erlang
Distance = distance({point, 34, 78}, {point, 67, -45}),
io:format("~.2f~n", [Distance]).
io:format("~.2f~n", [Distance]).
Distance = distance(point:new(34, 78), point:new(67, -45)),
io:format("~.2f~n", [Distance]).
io:format("~.2f~n", [Distance]).
csharp
System.Drawing.Point p = new System.Drawing.Point(13, 14),
p1 = new System.Drawing.Point(10, 10);
double distance = Math.Sqrt(Math.Pow(p1.X - p.X, 2) + Math.Pow(p1.Y - p.Y, 2)));
p1 = new System.Drawing.Point(10, 10);
double distance = Math.Sqrt(Math.Pow(p1.X - p.X, 2) + Math.Pow(p1.Y - p.Y, 2)));
Zero pad a number
Given the number 42, pad it to 8 characters like 00000042
perl
sprintf("%08d", 42);
erlang
Formatted = io_lib:format("~8..0B", [42]),
io:format("~8..0B~n", [42]).
csharp
string.Format("{0,8:D8}", 42);
Right Space pad a number
Given the number 1024 right pad it to 6 characters
"1024 "
perl
sprintf("%-6d", 1024);
erlang
Formatted = io_lib:format("~-6B", [1024]),
io:format("~-6B~n", [1024]).
csharp
public class NumberRightPadding {
public static void Main() {
string withStringDotFormat = string.Format("{0,-6}", 1024);
string withToStringDotPadRight = 1024.ToString().PadRight(6);
}
}
public static void Main() {
string withStringDotFormat = string.Format("{0,-6}", 1024);
string withToStringDotPadRight = 1024.ToString().PadRight(6);
}
}
Format a decimal number
Format the number 7/8 as a decimal with 2 places: 0.88
perl
sprintf("%.2f", 7/8);
erlang
Formatted = io_lib:format("~.2f", [7/8]),
io:format("~.2f~n", [7/8]).
csharp
public class FormatDecimal {
public static void Main() {
decimal result = decimal.Round( 7 / 8m, 2);
System.Console.WriteLine(result);
}
}
public static void Main() {
decimal result = decimal.Round( 7 / 8m, 2);
System.Console.WriteLine(result);
}
}
Left Space pad a number
Given the number 73 left pad it to 10 characters
" 73"
perl
sprintf("%10d", 73);
erlang
Formatted = io_lib:format("~10B", [73]),
io:format("~10B~n", [73]).
csharp
public class NumberLeftPadding {
public static void Main() {
string withStringDotFormat = string.Format("{0,10}", 73);
string withToStringDotPadLeft = 73.ToString().PadLeft(10);
}
}
public static void Main() {
string withStringDotFormat = string.Format("{0,10}", 73);
string withToStringDotPadLeft = 73.ToString().PadLeft(10);
}
}
Generate a random integer in a given range
Produce a random integer between 100 and 200 inclusive
perl
my $range = 100;
my $minimum = 100;
my $random_number = int(rand($range)) + $minimum;
print "$random_number\n";
my $minimum = 100;
my $random_number = int(rand($range)) + $minimum;
print "$random_number\n";
erlang
RandomInt = gen_rand_integer(100, 200),
csharp
System.Random r = new System.Random();
int random = r.Next(100,201);
int random = r.Next(100,201);
Generate a repeatable random number sequence
Initialise a random number generator with a seed and generate five decimal values. Reset the seed and produce the same values.
perl
srand(12345);
@list1 = map(int(rand(100)+1), (1..5));
srand(12345);
@list2 = map(int(rand(100)+1), (1..5));
print join(', ', @list1) . "\n";
print join(', ', @list2) . "\n";
@list1 = map(int(rand(100)+1), (1..5));
srand(12345);
@list2 = map(int(rand(100)+1), (1..5));
print join(', ', @list1) . "\n";
print join(', ', @list2) . "\n";
erlang
setRNG(RNGState),
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]),
setRNG(RNGState),
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]).
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]),
setRNG(RNGState),
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]).
csharp
using System;
public class RepeatableRandom {
public static void Main() {
var r = new Random(12); // seed is 12
for (int i = 0; i < 5; i++)
Console.WriteLine(r.Next());
r = new Random(12);
for (int i = 0; i < 5; i++)
Console.WriteLine(r.Next());
}
}
public class RepeatableRandom {
public static void Main() {
var r = new Random(12); // seed is 12
for (int i = 0; i < 5; i++)
Console.WriteLine(r.Next());
r = new Random(12);
for (int i = 0; i < 5; i++)
Console.WriteLine(r.Next());
}
}
Check if a string matches a regular expression
Display
"ok" if "Hello" matches /[A-Z][a-z]+/
perl
print 'ok' if ('Hello' =~ /[A-Z][a-z]+/);
erlang
String = "Hello", Regexp = "[A-Z][a-z]+",
is_match(String, Regexp) andalso (begin io:format("ok~n"), true end).
is_match(String, Regexp) andalso (begin io:format("ok~n"), true end).
case re:run("Hello", "[A-Z][a-z]+") of {match, _} -> ok end.
csharp
if (Regex.IsMatch("Hello", "[A-Z][a-z]+"))
{
Console.WriteLine("ok");
}
{
Console.WriteLine("ok");
}
Check if a string matches with groups
Display
"two" if "one two three" matches /one (.*) three/
perl
print $1 if "one two three"=~/^one (.*) three$/
erlang
case re:run("one two three", "one (.*) three", [{capture, [1], list}]) of {match, Res} -> hd(Res) end.
csharp
using System;
using System.Text.RegularExpressions;
public class RegexBackReference {
public static void Main() {
var oneTwoThree = "one two three";
var pattern = "one (.*) three";
Match match = Regex.Match(oneTwoThree, pattern);
// group 0 is the entire match. 1 is the first backreference
Console.WriteLine(match.Groups[1]);
}
}
using System.Text.RegularExpressions;
public class RegexBackReference {
public static void Main() {
var oneTwoThree = "one two three";
var pattern = "one (.*) three";
Match match = Regex.Match(oneTwoThree, pattern);
// group 0 is the entire match. 1 is the first backreference
Console.WriteLine(match.Groups[1]);
}
}
Check if a string contains a match to a regular expression
Display
"ok" if "abc 123 @#$" matches /\d+/
perl
print "ok" if ("abc 123 @#\$" =~ m/\d+/)
erlang
% Erlang uses 'egrep'-compatible regular expressions, so shortcuts like '\d' not supported
String = "abc 123 @#$", Regexp = "[0-9]+",
is_match(String, Regexp) andalso (begin io:format("ok~n"), true end).
String = "abc 123 @#$", Regexp = "[0-9]+",
is_match(String, Regexp) andalso (begin io:format("ok~n"), true end).
case re:run("abc 123 @#$", "\\d+") of {match, _} -> ok end.
csharp
if(System.Text.RegularExpressions.Regex.IsMatch("abc 123 @#$",@"\d+")){
Console.WriteLine("ok");
}
Console.WriteLine("ok");
}
Loop through a string matching a regex and performing an action for each match
Create a list
[fish1,cow3,boat4] when matching "(fish):1 sausage (cow):3 tree (boat):4" with regex /\((\w+)\):(\d+)/
perl
while ($text =~ /\((\w+)\):(\d+)/g) {
push @list, "$1$2"
}
push @list, "$1$2"
}
erlang
solve(S) ->
R = "\\((\\w+?)\\):(\\d+)",
{match, M} = re:run(S,R, [global, {capture, all_but_first, list}]),
[ A++N || [A, N] <- M].
R = "\\((\\w+?)\\):(\\d+)",
{match, M} = re:run(S,R, [global, {capture, all_but_first, list}]),
[ A++N || [A, N] <- M].
csharp
using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
public static class extensions {
public static IList<string> Map(this string me, string pattern, Func<Match, string> action){
IList<string> matches = new List<string>();
foreach (Match match in Regex.Matches(me,pattern)){
matches.Add(action(match));
}
return matches;
}
}
class Test
{
static void Main()
{
IList<string> list = "(fish):1 sausage (cow):3 tree (boat):4".Map(@"\((\w+)\):(\d+)", (m) => {return m.Groups[1].Value + m.Groups[2].Value;});
}
}
using System.Collections.Generic;
using System.Text.RegularExpressions;
public static class extensions {
public static IList<string> Map(this string me, string pattern, Func<Match, string> action){
IList<string> matches = new List<string>();
foreach (Match match in Regex.Matches(me,pattern)){
matches.Add(action(match));
}
return matches;
}
}
class Test
{
static void Main()
{
IList<string> list = "(fish):1 sausage (cow):3 tree (boat):4".Map(@"\((\w+)\):(\d+)", (m) => {return m.Groups[1].Value + m.Groups[2].Value;});
}
}
Replace the first regex match in a string with a static string
Transform
"Red Green Blue" into "R*d Green Blue" by replacing /e/ with "*"
perl
$text =~s/e/*/;
erlang
{ok, Replaced, _} = regexp:sub("Red Green Blue", "e", "*"),
re:replace("Red Green Blue", "e", "*", [{return, list}]).
Replace all regex matches in a string with a static string
Transform
"She sells sea shells" into "She X X shells" by replacing /se\w+/ with "X"
perl
$text = "She sells sea shells";
$text =~ s/se\w+/X/g;
$text =~ s/se\w+/X/g;
erlang
% Erlang uses 'egrep'-compatible regular expressions, so shortcuts like '\w' not supported
{ok, Replaced, _} = regexp:gsub("She sells sea shells", "se[A-Za-z0-9_]+", "X"),
{ok, Replaced, _} = regexp:gsub("She sells sea shells", "se[A-Za-z0-9_]+", "X"),
re:replace("She sells sea shells", "se\\w+", "X", [global, {return, list}]).
csharp
using System.Text.RegularExpressions;
class SolutionXX
{
static void Main()
{
string text = "She sells sea shells";
string result = Regex.Replace(text, @"se\w+", "X");
}
}
class SolutionXX
{
static void Main()
{
string text = "She sells sea shells";
string result = Regex.Replace(text, @"se\w+", "X");
}
}
Replace all regex matches in a string with a dynamic string
Transform
"The {Quick} Brown {Fox}" into "The kciuQ Brown xoF" by reversing words in braces using the regex /\{(\w+)\}/.
perl
$text = "The {Quick} Brown {Fox}";
$text =~ s/\{(\w+)\}/reverse($1)/ge;
$text =~ s/\{(\w+)\}/reverse($1)/ge;
erlang
% Erlang regular expressions lack both group capture and backreferences, thus this problem is not directly
% solvable. Presented solution is close, but not on-spec
String = "The {Quick} Brown {Fox}",
{match, FieldList} = regexp:matches(String, "\{([A-Za-z0-9_]+)\}"),
NewString = lists:foldl(fun ({Start, Length}, S) -> replstr(S, lists:reverse(string:substr(S, Start, Length)), Start) end, String, FieldList),
% solvable. Presented solution is close, but not on-spec
String = "The {Quick} Brown {Fox}",
{match, FieldList} = regexp:matches(String, "\{([A-Za-z0-9_]+)\}"),
NewString = lists:foldl(fun ({Start, Length}, S) -> replstr(S, lists:reverse(string:substr(S, Start, Length)), Start) end, String, FieldList),
Define an empty list
Assign the variable
"list" to a list with no elements
perl
@list = ();
erlang
List = [],
csharp
var list = new List<object>();
Define a static list
Define the list
[One, Two, Three, Four, Five]
perl
@list = qw(One Two Three Four Five);
@list = ('One', 'Two', 'Three', 'Four', 'Five');
erlang
List = [one, two, three, four, five],
List = ['One', 'Two', 'Three', 'Four', 'Five'],
csharp
IList<string> list = new string[]{"One","Two","Three","Four","Five"};
Join the elements of a list, separated by commas
Given the list
[Apple, Banana, Carrot] produce "Apple, Banana, Carrot"
perl
print join ', ', qw(Apple Banana Carrot);
# Longer and less efficient than join(), but illustrates
# Perl's foreach operator, which can be useful for
# less trivial problems with lists
@list = ('Apple', 'Banana', 'Carrot');
foreach $fruit (@list) {
print "$fruit,";
}
print "\n";
# Perl's foreach operator, which can be useful for
# less trivial problems with lists
@list = ('Apple', 'Banana', 'Carrot');
foreach $fruit (@list) {
print "$fruit,";
}
print "\n";
my @a = qw/Apple Banana Carrot/;
{
local $, = ", ";
print @a
}
print "\n";
{
local $, = ", ";
print @a
}
print "\n";
my @a = qw/Apple Banana Carrot/;
{
local $" = ", ";
print "@a\n";
}
{
local $" = ", ";
print "@a\n";
}
erlang
Result = string:join(Fruit, ", "),
Result = lists:foldl(fun (E, Acc) -> Acc ++ ", " ++ E end, hd(Fruit), tl(Fruit)),
Result = lists:flatten([ hd(Fruit) | [ ", " ++ X || X <- tl(Fruit)]]).
csharp
using System.Collections.Generic;
public class JoinEach {
public static void Main() {
var list = new List<string>() {"Apple", "Banana", "Carrot"};
System.Console.WriteLine( string.Join(", ", list.ToArray()) );
}
}
public class JoinEach {
public static void Main() {
var list = new List<string>() {"Apple", "Banana", "Carrot"};
System.Console.WriteLine( string.Join(", ", list.ToArray()) );
}
}
Join the elements of a list, in correct english
Create a function join that takes a List and produces a string containing an english language concatenation of the list. It should work with the following examples:
join(
join(
join(
join(
join(
[Apple, Banana, Carrot]) = "Apple, Banana, and Carrot"
join(
[One, Two]) = "One and Two"
join(
[Lonely]) = "Lonely"
join(
[]) = ""
perl
sub myjoin {
$_ = join ', ', @_;
s/, ([^,]+)$/ and $1/;
return $_;
}
# Note: I don't think this meets the spec --Geoff
$_ = join ', ', @_;
s/, ([^,]+)$/ and $1/;
return $_;
}
# Note: I don't think this meets the spec --Geoff
sub myjoin {
if ($#_ < 2) {
return join ' and ', @_;
} else {
return join(', ', @_[0..$#_-1]) . ' and ' . $_[-1];
}
}
# Note: I don't think this meets the spec --Geoff
if ($#_ < 2) {
return join ' and ', @_;
} else {
return join(', ', @_[0..$#_-1]) . ' and ' . $_[-1];
}
}
# Note: I don't think this meets the spec --Geoff
# Previous "myjoin()" responses don't meet the spec of including
# the final comma before the "and" if the list has more than
# two elements...this is one way to meet that spec...it may
# not be the most efficient...
sub AnotherMyJoin {
my @list = @_;
if ($#list == -1) {return}
elsif ($#list == 0) {return $list[0]}
elsif ($#list == 1) {return $list[0].' and '.$list[1]}
else {
return join(", ", @list[0..$#list - 1]) . ', and '. $list[$#list];
}
}
# the final comma before the "and" if the list has more than
# two elements...this is one way to meet that spec...it may
# not be the most efficient...
sub AnotherMyJoin {
my @list = @_;
if ($#list == -1) {return}
elsif ($#list == 0) {return $list[0]}
elsif ($#list == 1) {return $list[0].' and '.$list[1]}
else {
return join(", ", @list[0..$#list - 1]) . ', and '. $list[$#list];
}
}
# This is the long way, but it's kind of fun
# It illustrates the use of Perl's reverse()
# operator to work our way through the list
# elements backwards...I wrote this one before
# getting smart and looking at some of the other
# algorithms from the other languages. Still,
# it is only 12 lines of code vs 9 for my other
# solution if you disregard the comments.
sub myjoin {
my @list = reverse(@_); # Reverse original order of elements
my $retval;
# Make our exit here if we were passed an empty list
if ($#list == -1) {return}
# Loop through reversed elements in end-to-start order
for (0..$#list) {
# Add the reversed form of each element plus a space char
$retval .= reverse($list[$_]).' ';
# Add 'and' to lists with two or more elements
# placing it in between final and 'next to final'
$retval .= "dna " if ($#list > 0 and $_== 0);
# Add ',' to each element as long as there are more
# than two elements and the current element isn't the
# final element
$retval .= "," if ($#list > 1 and $_ != $#list);
}
# Remove what will end up as an extraneous leading space
chop($retval);
# Done looping, now reverse things back into correct order and return
$retval = reverse($retval);
return($retval);
}
# It illustrates the use of Perl's reverse()
# operator to work our way through the list
# elements backwards...I wrote this one before
# getting smart and looking at some of the other
# algorithms from the other languages. Still,
# it is only 12 lines of code vs 9 for my other
# solution if you disregard the comments.
sub myjoin {
my @list = reverse(@_); # Reverse original order of elements
my $retval;
# Make our exit here if we were passed an empty list
if ($#list == -1) {return}
# Loop through reversed elements in end-to-start order
for (0..$#list) {
# Add the reversed form of each element plus a space char
$retval .= reverse($list[$_]).' ';
# Add 'and' to lists with two or more elements
# placing it in between final and 'next to final'
$retval .= "dna " if ($#list > 0 and $_== 0);
# Add ',' to each element as long as there are more
# than two elements and the current element isn't the
# final element
$retval .= "," if ($#list > 1 and $_ != $#list);
}
# Remove what will end up as an extraneous leading space
chop($retval);
# Done looping, now reverse things back into correct order and return
$retval = reverse($retval);
return($retval);
}
# Yes, this doesn't meet the spec, the spec is flawed
# the serial comma (Oxford comma) is not required in a list
sub english_join {
return join(', ', @_[0..$#_-1])
. ($#_ ? ' and ' : '' )
. $_[-1];
}
# the serial comma (Oxford comma) is not required in a list
sub english_join {
return join(', ', @_[0..$#_-1])
. ($#_ ? ' and ' : '' )
. $_[-1];
}
erlang
io:format("~s~n", [join(Fruit)]).
% ------
join([]) -> "";
join([W|Ws]) -> join(Ws, W).
join([], S) -> S;
join([W], S) -> join([], S ++ " and " ++ W);
join([W|Ws], S) -> join(Ws, S ++ ", " ++ W).
% ------
join([]) -> "";
join([W|Ws]) -> join(Ws, W).
join([], S) -> S;
join([W], S) -> join([], S ++ " and " ++ W);
join([W|Ws], S) -> join(Ws, S ++ ", " ++ W).
%% According to the reference manual, "string is not a data type in Erlang."
%% Instead it has lists of integers. But I/O functions in general accept
%% IO lists, where an IO list is either a list of IO lists or an integer.
%% This gives you O(1) string concatenation.
-module(commalist).
-export([join/1]).
join([]) -> "";
join([W]) -> W;
join([W1, W2]) -> [W1, " and ", W2];
join([W1, W2, W3]) -> [W1, ", ", W2, ", and ", W3];
join([W1|Ws]) -> [W1, ", ", join(Ws)].
%% Instead it has lists of integers. But I/O functions in general accept
%% IO lists, where an IO list is either a list of IO lists or an integer.
%% This gives you O(1) string concatenation.
-module(commalist).
-export([join/1]).
join([]) -> "";
join([W]) -> W;
join([W1, W2]) -> [W1, " and ", W2];
join([W1, W2, W3]) -> [W1, ", ", W2, ", and ", W3];
join([W1|Ws]) -> [W1, ", ", join(Ws)].
csharp
using System.Collections.Generic;
using System.Linq;
public class CSharpListToEnglishList {
public string JoinAsEnglishList (List<string> words) {
switch (words.Count) {
case 0: return "";
case 1: return words[0];
case 2: return string.Format("{0} and {1}", words.ToArray());
default:
return JoinAsEnglishList( new List<string>() {
string.Join(", ", words.Take(words.Count - 1).ToArray()) + ",",
words.Last()
});
}
}
// Driver...
public static void Main() {
var joiner = new CSharpListToEnglishList();
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "Apple", "Banana", "Carrot", "Orange" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "Apple", "Banana", "Carrot" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "One", "Two" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "Lonely" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>()) );
}
}
using System.Linq;
public class CSharpListToEnglishList {
public string JoinAsEnglishList (List<string> words) {
switch (words.Count) {
case 0: return "";
case 1: return words[0];
case 2: return string.Format("{0} and {1}", words.ToArray());
default:
return JoinAsEnglishList( new List<string>() {
string.Join(", ", words.Take(words.Count - 1).ToArray()) + ",",
words.Last()
});
}
}
// Driver...
public static void Main() {
var joiner = new CSharpListToEnglishList();
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "Apple", "Banana", "Carrot", "Orange" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "Apple", "Banana", "Carrot" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "One", "Two" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>() { "Lonely" }) );
System.Console.WriteLine(
joiner.JoinAsEnglishList(new List<string>()) );
}
}
Produce the combinations from two lists
Given two lists, produce the list of tuples formed by taking the combinations from the individual lists. E.g. given the letters
["a", "b", "c"] and the numbers [4, 5], produce the list: [["a", 4], ["b", 4], ["c", 4], ["a", 5], ["b", 5], ["c", 5]]
perl
@letters = qw(a b c);
@numbers = (4, 5);
@list = map { $number=$_; map [$_, $number], @letters; } @numbers;
@numbers = (4, 5);
@list = map { $number=$_; map [$_, $number], @letters; } @numbers;
@letters = qw(a b c);
@numbers = (4, 5);
for $number (@numbers) {
for $letter (@letters) {
push @list, [$letter, $number];
}
}
@numbers = (4, 5);
for $number (@numbers) {
for $letter (@letters) {
push @list, [$letter, $number];
}
}
erlang
Combinations =
lists:foldl(fun (Number, Acc) -> Acc ++ lists:map(fun (Letter) -> {Letter, Number} end, Letters) end, [], Numbers),
lists:foldl(fun (Number, Acc) -> Acc ++ lists:map(fun (Letter) -> {Letter, Number} end, Letters) end, [], Numbers),
Combinations = lists:keysort(2, sofs:to_external(sofs:product(sofs:set(Letters), sofs:set(Numbers))))
[[A, B] || A <- ["a", "b", "c"], B <- [4, 5]].
csharp
using System.Collections.Generic;
public class ListCombiner {
public static void Main() {
var letters = new List<char>() { 'a', 'b', 'c' };
var numbers = new List<int>() { 1, 2, 3 };
// result is a list that contaings lists of objects
var result = new List<List<object>>();
foreach (var l in letters) {
foreach (var n in numbers) {
result.Add(new List<object>() { l, n });
}
}
}
}
public class ListCombiner {
public static void Main() {
var letters = new List<char>() { 'a', 'b', 'c' };
var numbers = new List<int>() { 1, 2, 3 };
// result is a list that contaings lists of objects
var result = new List<List<object>>();
foreach (var l in letters) {
foreach (var n in numbers) {
result.Add(new List<object>() { l, n });
}
}
}
}
From a List Produce a List of Duplicate Entries
Taking a list:
Write the code to produce a list of duplicates in the list:
["andrew", "bob", "chris", "bob"]
Write the code to produce a list of duplicates in the list:
["bob"]
perl
my @input = ("andrew", "bob", "chris", "bob", "bob");
my %input_count;
my @output = grep { $input_count{$_}++; $input_count{$_} == 2 } @input;
my %input_count;
my @output = grep { $input_count{$_}++; $input_count{$_} == 2 } @input;
erlang
{_, Result} = lists:foldl(
fun(X, {Uniq, Dupl}) -> case lists:member(X, Uniq) of
true -> {Uniq,[X | Dupl]};
_ -> {[X | Uniq], Dupl}
end
end,
{[], []},
List),
fun(X, {Uniq, Dupl}) -> case lists:member(X, Uniq) of
true -> {Uniq,[X | Dupl]};
_ -> {[X | Uniq], Dupl}
end
end,
{[], []},
List),
Fun = fun
([X | Xs], F) -> case lists:member(X, Xs) of
true -> [X | F(Xs, F)];
_ -> F(Xs, F)
end;
([], _) -> []
end,
Result = Fun(List, Fun).
([X | Xs], F) -> case lists:member(X, Xs) of
true -> [X | F(Xs, F)];
_ -> F(Xs, F)
end;
([], _) -> []
end,
Result = Fun(List, Fun).
csharp
List<String> values = new List<string> {"andrew", "bob", "chris", "bob"};
var duplicates = values
.GroupBy(i => i)
.Where(j => j.Count() > 1)
.Select(s => s.Key);
foreach (var duplicate in duplicates)
{
Console.WriteLine(duplicate);
}
var duplicates = values
.GroupBy(i => i)
.Where(j => j.Count() > 1)
.Select(s => s.Key);
foreach (var duplicate in duplicates)
{
Console.WriteLine(duplicate);
}
Fetch an element of a list by index
Given the list
[One, Two, Three, Four, Five], fetch the third element ('Three')
perl
qw(One Two Three Four Five)[2];
@list = qw(One Two Three Four Five);
$list[2];
$list[2];
erlang
Result = lists:nth(3, List),
Result = element(3, list_to_tuple(List)),
{Left, _} = lists:split(3, List), Result = lists:last(Left),
Result = nth0(2, List),
csharp
string[] items = new string[] { "One", "Two", "Three", "Four", "Five" };
List<string> list = new List<string>(items);
string third = list[2]; // "Three"
List<string> list = new List<string>(items);
string third = list[2]; // "Three"
// Make sure you import the System.Linq namespace.
// This is not the preferred way of indexing if you are using Lists.
string[] items = new string[] { "One", "Two", "Three", "Four", "Five" };
IEnumerable<string> list = new List<string>(items);
string third = list.ElementAt(2); // Three
// This is not the preferred way of indexing if you are using Lists.
string[] items = new string[] { "One", "Two", "Three", "Four", "Five" };
IEnumerable<string> list = new List<string>(items);
string third = list.ElementAt(2); // Three
Fetch the last element of a list
Given the list
[Red, Green, Blue], access the last element ('Blue')
perl
qw(Red Green Blue)[-1];
@list = qw(Red Green Blue);
$list[-1];
$list[-1];
erlang
Result = lists:last(List),
Result = last(List),
Result = hd(lists:reverse(List)),
Result = lists:nth(length(List), List),
csharp
string[] items = new string[] { "Red", "Green", "Blue" };
List<string> list = new List<string>(items);
string last = list[list.Count - 1]; // "Blue"
List<string> list = new List<string>(items);
string last = list[list.Count - 1]; // "Blue"
// Make sure you import the System.Linq namespace.
// This is not the preferred way of finding the last element if you are using Lists.
string[] items = new string[] { "Red", "Green", "Blue" };
IEnumerable<string> list = new List<string>(items);
string last = list.Last(); // "Blue"
// This is not the preferred way of finding the last element if you are using Lists.
string[] items = new string[] { "Red", "Green", "Blue" };
IEnumerable<string> list = new List<string>(items);
string last = list.Last(); // "Blue"
Find the common items in two lists
Given two lists, find the common items. E.g. given beans =
['broad', 'mung', 'black', 'red', 'white'] and colors = ['black', 'red', 'blue', 'green'], what are the bean varieties that are also color names?
perl
@beans = qw(broad mung black red white);
@colors = qw(black red blue green);
@seen{@beans} = ();
for (@colors) {
push(@intersection, $_) if exists($seen{$_});
}
print join(', ', @intersection);
@colors = qw(black red blue green);
@seen{@beans} = ();
for (@colors) {
push(@intersection, $_) if exists($seen{$_});
}
print join(', ', @intersection);
@beans = qw(broad mung black red white);
@colors = qw(black red blue green);
my %colors_hash = map { $_ => 1 } @colors;
my @intersection = grep { $colors_hash{$_} } @beans;
print join(', ', @intersection),"\n";
@colors = qw(black red blue green);
my %colors_hash = map { $_ => 1 } @colors;
my @intersection = grep { $colors_hash{$_} } @beans;
print join(', ', @intersection),"\n";
@beans = qw/broad mung black red white/;
@colors = qw/black red blue green/;
print join ', ', grep { $_ ~~ @colors } @beans;
@colors = qw/black red blue green/;
print join ', ', grep { $_ ~~ @colors } @beans;
erlang
Beans = sets:from_list([broad, mung, black, red, white]), Colors = sets:from_list([black, red, blue, green]),
Common = sets:to_list(sets:intersection(Beans, Colors)),
Common = sets:to_list(sets:intersection(Beans, Colors)),
csharp
// Make sure you import the System.Linq namespace.
// This example uses arrays as the underlying implementation, but any IEnumerable type can be used - including List.
IEnumerable<string> beans = new string[] { "beans", "mung", "black", "red", "white" };
IEnumerable<string> colors = new string[] { "black", "red", "blue", "green" };
var intersect = beans.Intersect(colors); // ['red', 'black']
// This example uses arrays as the underlying implementation, but any IEnumerable type can be used - including List.
IEnumerable<string> beans = new string[] { "beans", "mung", "black", "red", "white" };
IEnumerable<string> colors = new string[] { "black", "red", "blue", "green" };
var intersect = beans.Intersect(colors); // ['red', 'black']
Display the unique items in a list
Display the unique items in a list, e.g. given ages =
[18, 16, 17, 18, 16, 19, 14, 17, 19, 18], display the unique elements, i.e. with duplicates removed.
perl
@ages = (18, 16, 17, 18, 16, 19, 14, 17, 19, 18);
@seen{@ages} = ();
@unique = keys %seen;
print join(', ', @unique);
@seen{@ages} = ();
@unique = keys %seen;
print join(', ', @unique);
@ages = (18, 16, 17, 18, 16, 19, 14, 17, 19, 18);
@unique = grep(!$seen{$_}++, @ages);
print join(', ', @unique);
@unique = grep(!$seen{$_}++, @ages);
print join(', ', @unique);
@ages = (18, 16, 17, 18, 16, 19, 14, 17, 19, 18);
print join(', ', grep(!$seen{$_}++, @ages));
print join(', ', grep(!$seen{$_}++, @ages));
@ages = (18, 16, 17, 18, 16, 19, 14, 17, 19, 18);
for (@ages) {
push(@unique, $_) unless $seen{$_}++;
}
print join(', ', @unique);
for (@ages) {
push(@unique, $_) unless $seen{$_}++;
}
print join(', ', @unique);
use List::MoreUtils qw(uniq);
@ages = (18, 16, 17, 18, 16, 19, 14, 17, 19, 18);
print join(', ', uniq(@ages));
@ages = (18, 16, 17, 18, 16, 19, 14, 17, 19, 18);
print join(', ', uniq(@ages));
erlang
Ages = sets:to_list(sets:from_list([18, 16, 17, 18, 16, 19, 14, 17, 19, 18])), io:format("~w~n", [Ages]).
lists:usort([18, 16, 17, 18, 16, 19, 14, 17, 19, 18]).
csharp
using System.Collections.Generic;
using System.Linq;
public class UniqueElements {
public static void Main() {
var list = new List<int>() { 18, 16, 17, 18, 16, 19, 14, 17, 19, 18 };
var uniques = list.Distinct();
}
}
using System.Linq;
public class UniqueElements {
public static void Main() {
var list = new List<int>() { 18, 16, 17, 18, 16, 19, 14, 17, 19, 18 };
var uniques = list.Distinct();
}
}
Remove an element from a list by index
Given the list
[Apple, Banana, Carrot], remove the first element to produce the list [Banana, Carrot]
perl
@list = qw(Apple Banana Carrot);
shift @list;
shift @list;
@list = qw(Apple Banana Carrot);
$offset = 0;
splice(@list, $offset, 1);
$offset = 0;
splice(@list, $offset, 1);
erlang
Result = tl(List),
[_|Result] = List,
N = 1, {Left, Right} = lists:split(N - 1, List), Result = Left ++ tl(Right),
Result = drop(1, List),
csharp
class Solution1516
{
static void Main()
{
List<string> fruit = new List<string>() { "Apple", "Banana", "Carrot" };
fruit.RemoveAt(0);
}
}
{
static void Main()
{
List<string> fruit = new List<string>() { "Apple", "Banana", "Carrot" };
fruit.RemoveAt(0);
}
}
Remove the last element of a list
perl
pop @list;
erlang
Result = init(List),
Result = take(length(List) - 1, List),
Result = lists:reverse(tl(lists:reverse(List))),
csharp
List<string> fruits = new List() { "apple", "banana", "cherry" };
fruits.RemoveAt(fruits.Length - 1);
fruits.RemoveAt(fruits.Length - 1);
Rotate a list
Given a list
["apple", "orange", "grapes", "bananas"], rotate it by removing the first item and placing it on the end to yield ["orange", "grapes", "bananas", "apple"]
perl
@list = qw(apple, orange, grapes, bananas);
push @list, shift @list;
push @list, shift @list;
@list = qw(apple orange grapes bananas);
@list = @list[1..$#list,0];
@list = @list[1..$#list,0];
erlang
N = 1, {Left, Right} = lists:split(N, List), Result = Right ++ Left,
N = 1, Result = rotate(N, List),
csharp
var lst = new LinkedList<String>(new String[] {"apple", "orange", "grapes", "banana"});
lst.AddLast(lst.First());
lst.DeleteFirst();
lst.AddLast(lst.First());
lst.DeleteFirst();
Gather together corresponding elements from multiple lists
Given several lists, gather together the first element from every list, the second element from every list, and so on for all corresponding index values in the lists. E.g. for these three lists, first =
['Bruce', 'Tommy Lee', 'Bruce'], last = ['Willis', 'Jones', 'Lee'], years = [1955, 1946, 1940] the result should produce 3 actors. The middle actor should be Tommy Lee Jones.
perl
my @first = ('Bruce', 'Tommy Lee', 'Bruce');
my @last = ('Willis', 'Jones', 'Lee');
my @years = (1955, 1946, 1940);
my @actors;
my $max = scalar @first;
for my $index (0 .. $max) {
push @actors, [ $first[$index], $last[$index], $years[$index] ];
};
my @last = ('Willis', 'Jones', 'Lee');
my @years = (1955, 1946, 1940);
my @actors;
my $max = scalar @first;
for my $index (0 .. $max) {
push @actors, [ $first[$index], $last[$index], $years[$index] ];
};
erlang
First = ['Bruce', 'Tommy Lee', 'Bruce'], Last = ['Willis', 'Jones', 'Lee'], Years = [1955, 1946, 1940],
Result = lists:zip3(First, Last, Years),
Result = lists:zip3(First, Last, Years),
csharp
String[] first = { "Bruce", "Tommy Lee", "Bruce" };
String[] last = { "Willis", "Jones", "Lee" };
int[] years = { 1955, 1946, 1940 };
var actors = first.Zip(last, (f, l) => Tuple.Create(f, l)).Zip(years, (t, y) => Tuple.Create(t.Item1, t.Item2, y)).ToArray();
Debug.Assert(actors[1].Equals(Tuple.Create("Tommy Lee", "Jones", 1946)));
String[] last = { "Willis", "Jones", "Lee" };
int[] years = { 1955, 1946, 1940 };
var actors = first.Zip(last, (f, l) => Tuple.Create(f, l)).Zip(years, (t, y) => Tuple.Create(t.Item1, t.Item2, y)).ToArray();
Debug.Assert(actors[1].Equals(Tuple.Create("Tommy Lee", "Jones", 1946)));
List Combinations
Given two source lists (or sets), generate a list (or set) of all the pairs derived by combining elements from the individual lists (sets). E.g. given suites =
['H', 'D', 'C', 'S'] and faces = ['2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K', 'A'], generate the deck of 52 cards, confirm the deck size and check it contains an expected card, say 'Ace of Hearts'.
perl
@suites = qw(H D C S);
@faces = qw(2 3 4 5 6 7 8 9 10 J Q K A);
@deck = map { $suite=$_; map $suite.$_, @faces; } @suites;
print 'checking deck size: ' . (@deck == 52 ? 'pass' : 'fail') . "\n";
print 'deck contains "Ace of Hearts": ' . (grep(/^HA$/, @deck) ? 'true' : 'false') . "\n";
@faces = qw(2 3 4 5 6 7 8 9 10 J Q K A);
@deck = map { $suite=$_; map $suite.$_, @faces; } @suites;
print 'checking deck size: ' . (@deck == 52 ? 'pass' : 'fail') . "\n";
print 'deck contains "Ace of Hearts": ' . (grep(/^HA$/, @deck) ? 'true' : 'false') . "\n";
erlang
Cards = lists:foldl(fun (Suite, Acc) -> Acc ++ lists:flatmap(fun (Face) -> [{Suite, Face}] end, Faces) end, [], Suites),
io:format("Deck has ~B cards~n", [length(Cards)]),
IsMember = lists:member({h, 'A'}, Cards),
io:format("~s~n", [if IsMember -> "Deck contains 'Ace of Hearts'" ; true -> "'Ace of Hearts' not in deck" end]),
io:format("Deck has ~B cards~n", [length(Cards)]),
IsMember = lists:member({h, 'A'}, Cards),
io:format("~s~n", [if IsMember -> "Deck contains 'Ace of Hearts'" ; true -> "'Ace of Hearts' not in deck" end]),
Cards = sofs:to_external(sofs:product(sofs:set(Suites), sofs:set(Faces))),
io:format("Deck has ~B cards~n", [length(Cards)]),
IsMember = lists:member({h, 'A'}, Cards),
io:format("~s~n", [if IsMember -> "Deck contains 'Ace of Hearts'" ; true -> "'Ace of Hearts' not in deck" end]),
io:format("Deck has ~B cards~n", [length(Cards)]),
IsMember = lists:member({h, 'A'}, Cards),
io:format("~s~n", [if IsMember -> "Deck contains 'Ace of Hearts'" ; true -> "'Ace of Hearts' not in deck" end]),
Deck2 = [{S, V} || S <- [d, c, h, s], V <- [2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K', 'A']],
52 = length(Deck2),
true = lists:member({h, 'A'}, Deck2).
52 = length(Deck2),
true = lists:member({h, 'A'}, Deck2).
csharp
using System;
using System.Collections.Generic;
using System.Linq;
namespace Combinations
{
class Program
{
public static void Main(string[] args)
{
// Define the given lists
// Since List`1 implements the interface IEnumerable`1, this can easily be redefined as List`1.
IEnumerable<string> suites = new string[] { "H", "D", "C", "S" };
IEnumerable<string> faces = new string[] { "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K", "A" };
// LINQ Query to perform a Cartesian product and create an anonymous type to hold the results.
// "var" is required to define this as an IEnumerable`1
var deck =
from suite in suites // For each suite in suites
from face in faces // Match it with a face in face.
select new
{
Suite = suite,
Face = face
};
// Verify the count (uses LINQ extension)
if (deck.Count() == 52)
{
Console.WriteLine("Count matches!");
}
// Verify that the Ace of Hearts is in the deck (uses LINQ extension)
if (deck.Contains(new {Suite = "H", Face = "A"}))
{
Console.WriteLine("Ace of Hearts found!");
}
// Example of how to iterate through the list.
// "var" here is required since we are using an anonymous type
foreach(var card in deck)
{
Console.WriteLine("Suite: {0} Face: {1}", card.Suite, card.Face);
}
// If you desire to work with a List`1, you can convert this to a normal list at any time:
Console.WriteLine("\nConverting to list!");
var list = deck.ToList();
Console.WriteLine("Suite: {0} Face: {1}", list[5].Suite, list[5].Face);
Console.WriteLine("List count: {0}", list.Count); // 52
Console.ReadLine();
}
}
}
using System.Collections.Generic;
using System.Linq;
namespace Combinations
{
class Program
{
public static void Main(string[] args)
{
// Define the given lists
// Since List`1 implements the interface IEnumerable`1, this can easily be redefined as List`1.
IEnumerable<string> suites = new string[] { "H", "D", "C", "S" };
IEnumerable<string> faces = new string[] { "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K", "A" };
// LINQ Query to perform a Cartesian product and create an anonymous type to hold the results.
// "var" is required to define this as an IEnumerable`1
var deck =
from suite in suites // For each suite in suites
from face in faces // Match it with a face in face.
select new
{
Suite = suite,
Face = face
};
// Verify the count (uses LINQ extension)
if (deck.Count() == 52)
{
Console.WriteLine("Count matches!");
}
// Verify that the Ace of Hearts is in the deck (uses LINQ extension)
if (deck.Contains(new {Suite = "H", Face = "A"}))
{
Console.WriteLine("Ace of Hearts found!");
}
// Example of how to iterate through the list.
// "var" here is required since we are using an anonymous type
foreach(var card in deck)
{
Console.WriteLine("Suite: {0} Face: {1}", card.Suite, card.Face);
}
// If you desire to work with a List`1, you can convert this to a normal list at any time:
Console.WriteLine("\nConverting to list!");
var list = deck.ToList();
Console.WriteLine("Suite: {0} Face: {1}", list[5].Suite, list[5].Face);
Console.WriteLine("List count: {0}", list.Count); // 52
Console.ReadLine();
}
}
}
Perform an operation on every item of a list
Perform an operation on every item of a list, e.g.
for the list
the list of sizes of the strings, e.g.
for the list
["ox", "cat", "deer", "whale"] calculate
the list of sizes of the strings, e.g.
[2, 3, 4, 5]
perl
my @list = qw{ox cat deer whale};
my @lengths = map {length($_)} @list;
print "@list\n";
print "@lengths\n";
my @lengths = map {length($_)} @list;
print "@list\n";
print "@lengths\n";
erlang
lists:map(fun (X) ->length(X) end, List).
csharp
using System.Collections.Generic;
public class OperationOnEach {
public static void Main() {
var list = new List<string>() { "ox", "cat", "deer", "whale" };
list.ForEach( System.Console.WriteLine );
}
}
public class OperationOnEach {
public static void Main() {
var list = new List<string>() { "ox", "cat", "deer", "whale" };
list.ForEach( System.Console.WriteLine );
}
}
Split a list of things into numbers and non-numbers
Given a list that might contain e.g. a string, an integer, a float and a date,
split the list into numbers and non-numbers.
split the list into numbers and non-numbers.
perl
use Scalar::Util qw(looks_like_number);
my @things = ('hello',25,3.14,scalar(localtime(time)));
my @numbers;
my @others;
for ( @things ) {
if ( looks_like_number $_ ) {
push @numbers, $_;
} else {
push @other, $_;
}
}
my @things = ('hello',25,3.14,scalar(localtime(time)));
my @numbers;
my @others;
for ( @things ) {
if ( looks_like_number $_ ) {
push @numbers, $_;
} else {
push @other, $_;
}
}
erlang
% Wrapped call to the auxiliary function
number_split(Xs) ->
number_split(Xs, [], []).
% The auxiliary function
number_split([], Num, NonNum) ->
{Num, NonNum};
number_split([X|Xs], Num, NonNum) ->
case is_number(X) of
true ->
number_split(Xs, [X|Num], NonNum);
false ->
number_split(Xs, Num, [X|NonNum])
end.
number_split(Xs) ->
number_split(Xs, [], []).
% The auxiliary function
number_split([], Num, NonNum) ->
{Num, NonNum};
number_split([X|Xs], Num, NonNum) ->
case is_number(X) of
true ->
number_split(Xs, [X|Num], NonNum);
false ->
number_split(Xs, Num, [X|NonNum])
end.
List = ["hello", 25, 3.14, calendar:local_time()],
{Numbers, NonNumbers} = lists:partition(fun(E) -> is_number(E) end, List)
{Numbers, NonNumbers} = lists:partition(fun(E) -> is_number(E) end, List)
csharp
using System;
using System.Collections.Generic;
using System.Linq;
// AFAIK, there just isn't a good way to do this in C#
public class ListSplitter {
public static bool IsNumeric(object o) {
var d = new Decimal();
return decimal.TryParse(o.ToString(), out d);
}
public static void Main() {
var list = new List<object>() { "foo", DateTime.Now, 1, "bar", 2.4 };
// the Where method does the work...
var numbers = list.Where( el => IsNumeric(el) );
var nonNumbers = list.Where( el => ! IsNumeric(el) );
}
}
using System.Collections.Generic;
using System.Linq;
// AFAIK, there just isn't a good way to do this in C#
public class ListSplitter {
public static bool IsNumeric(object o) {
var d = new Decimal();
return decimal.TryParse(o.ToString(), out d);
}
public static void Main() {
var list = new List<object>() { "foo", DateTime.Now, 1, "bar", 2.4 };
// the Where method does the work...
var numbers = list.Where( el => IsNumeric(el) );
var nonNumbers = list.Where( el => ! IsNumeric(el) );
}
}
Test if a condition holds for all items of a list
Given a list, test if a certain logical condition (i.e. predicate) holds for all items of the list.
erlang
Result = lists:all(Pred, List).
Test if a condition holds for any items of a list
Given a list, test if a certain logical condition (i.e. predicate) holds for any items of the list.
erlang
Result = lists:any(Pred, List).
Define an empty map
perl
# %map = {}
# This was wrong, that would have created a hash with one key
# of the stringified hash reference (HASH(0xNUMBERSHERE)) and a
# value of 'undef', as well as triggering a
# "Reference found where even-sized list expected" with the warnings
# pragma enabled
my %map;
# This was wrong, that would have created a hash with one key
# of the stringified hash reference (HASH(0xNUMBERSHERE)) and a
# value of 'undef', as well as triggering a
# "Reference found where even-sized list expected" with the warnings
# pragma enabled
my %map;
erlang
Map = dict:new(),
Map = orddict:new(),
Map = gb_trees:empty(),
Map = ets:new(the_map_name, [set, private, {keypos, 1}]),
Define an unmodifiable empty map
perl
# perl does not provide unmodifiable maps/hashes, but you could use "constant
# functions", if you really need them
# 2011-07-06 Not actually true, see Hash::Util::lock_hash;
sub MAP () { {} }
# functions", if you really need them
# 2011-07-06 Not actually true, see Hash::Util::lock_hash;
sub MAP () { {} }
use Hash::Util qw/lock_hash/;
# two lines
my %hash;
lock_hash(%hash);
# or in one line
lock_hash(my %locked_hash);
# two lines
my %hash;
lock_hash(%hash);
# or in one line
lock_hash(my %locked_hash);
erlang
% Erlang data structures are immutable - updating a 'map' sees a modified copy created
Map = dict:new(),
% Erlang data structures are immutable - updating a 'map' sees a modified copy created
Map = dict:new(),
Define an initial map
Define the map
{circle:1, triangle:3, square:4}
perl
%map = (circle => 1, triangle => 3, square => 4);
erlang
Map = dict:from_list([{circle, 1}, {triangle, 3}, {square, 4}]),
Map0 = dict:new(),
% Erlang variables are 'single-assignment' i.e. they cannot be reassigned
Map1 = dict:store(circle, 1, Map0),
Map2 = dict:store(triangle, 3, Map1),
Map3 = dict:store(square, 4, Map2),
% Erlang variables are 'single-assignment' i.e. they cannot be reassigned
Map1 = dict:store(circle, 1, Map0),
Map2 = dict:store(triangle, 3, Map1),
Map3 = dict:store(square, 4, Map2),
Map0 = gb_trees:empty(),
Map1 = gb_trees:enter(circle, 1, Map0),
Map2 = gb_trees:enter(triangle, 3, Map1),
Map3 = gb_trees:enter(square, 4, Map2),
Map1 = gb_trees:enter(circle, 1, Map0),
Map2 = gb_trees:enter(triangle, 3, Map1),
Map3 = gb_trees:enter(square, 4, Map2),
Map = gb_trees:from_orddict(lists:keysort(1, [{circle, 1}, {triangle, 3}, {square, 4}])),
Map = ets:new(the_map_name, [ordered_set, private, {keypos, 1}]),
ets:insert(Map, [{circle, 1}, {triangle, 3}, {square, 4}]),
ets:insert(Map, [{circle, 1}, {triangle, 3}, {square, 4}]),
Check if a key exists in a map
Given a map pets
{joe:cat,mary:turtle,bill:canary} print "ok" if an pet exists for "mary"
perl
%pets = (joe => 'cat', mary => 'turtle', bill => 'canary');
print 'ok' if ($pets{'mary'});
print 'ok' if ($pets{'mary'});
%pets = (joe => 'cat', mary => 'turtle', bill => 'canary');
print 'ok' if $pets{'mary'};
print 'ok' if $pets{'mary'};
print 'ok' if $pets{mary};
print 'ok' if exists $pets{mary}
erlang
dict:is_key(mary, Pets) andalso begin io:format("ok~n"), true end.
IsMember = ets:member(Pets, mary), if (IsMember) -> io:format("ok~n") ; true -> false end.
case gb_trees:lookup(mary, Pets) of none -> false ; _ -> io:format("ok~n") end.
Retrieve a value from a map
Given a map pets
{joe:cat,mary:turtle,bill:canary} print the pet for "joe" ("cat")
perl
%pets = (joe => 'cat', mary => 'turtle', bill=>'canary');
print $pets{joe};
print $pets{joe};
erlang
dict:is_key(joe, Pets) andalso begin io:format("~w~n", [dict:fetch(joe, Pets)]), true end.
case dict:find(joe, Pets) of error -> false ; {ok, Pet} -> io:format("~w~n", [Pet]) end.
IsMember = ets:member(Pets, joe), if (IsMember) -> io:format("~w~n", [ets:lookup_element(Pets, joe, 2)]) ; true -> false end.
case ets:match(Pets, {joe, '$1'}) of [] -> false ; [[Pet]] -> io:format("~w~n", [Pet]) end.
case gb_trees:lookup(joe, Pets) of none -> false ; {value, Pet} -> io:format("~w~n", [Pet]) end.
Add an entry to a map
Given an empty pets map, add the mapping from
"rob" to "dog"
perl
$pets{rob} = 'dog';
erlang
Pets1 = dict:store(rob, dog, Pets0).
ets:insert(Pets, {rob, dog}).
Pets1 = gb_trees:enter(rob, dog, Pets0).
Remove an entry from a map
Given a map pets
{joe:cat,mary:turtle,bill:canary} remove the mapping for "bill" and print "canary"
perl
print delete $pets{bill};
erlang
Pet = dict:fetch(bill, Pets0), Pets1 = dict:erase(bill, Pets0), io:format("~w~n", [Pet]),
Pet = ets:lookup_element(Pets, bill, 2), ets:delete(Pets, bill), io:format("~w~n", [Pet]),
{value, Pet} = gb_trees:lookup(bill, Pets0), Pets1 = gb_trees:delete(bill, Pets0), io:format("~w~n", [Pet]),
Create a histogram map from a list
Given the list
[a,b,a,c,b,b], produce a map {a:2, b:3, c:1} which contains the count of each unique item in the list
perl
foreach(@list) {
$histogram{$_}++;
}
$histogram{$_}++;
}
$histogram{$_}++ for @list;
erlang
% Imperative Solution
Histogram = histogram(List),
Histogram = histogram(List),
% Functional (1) Solution
Histogram = histogram(List),
Histogram = histogram(List),
lists:foldl(fun(Elem, OldDict) ->
dict:update_counter(Elem, 1, OldDict)
end,
dict:new(),
[a,b,a,c,b,b])).
dict:update_counter(Elem, 1, OldDict)
end,
dict:new(),
[a,b,a,c,b,b])).
csharp
using System.Collections.Generic;
using System.Linq;
// This is a "functional" C# approach
// NOTE: In C# "maps" are of type Dictionary<Tkey, TValue>
// so our histogram map is of type Dictionary<object, int>
public class HistogramMap {
public Dictionary<object, int> FromList(List<object> list) {
// The "Aggregate" method works like "inject" in many other languages.
return list.Aggregate(
new Dictionary<object, int>(),
(map, obj) => {
// If this is the first time we've seen this obj, set the count to 0
if (!map.ContainsKey(obj)) map[obj] = 0;
// Increment the count
map[obj]++;
// Return the map for the next iteration.
// NOTE: This does NOT return from our "FromList" method
return map;
}
);
}
public static void Main() {
// Create our Histogram Map from a new list
var map = new HistogramMap().FromList(
new List<object>() { 'a', 'b', 'a', 'c', 'b', 'b' }
);
// This just prints the result
System.Console.WriteLine (
string.Join (", ",
// "Select" works like "map" or "collect" in many other languages
map.Select( kvp =>
string.Format("{0} : {1}", kvp.Key, kvp.Value)
).ToArray()
)
);
}
}
using System.Linq;
// This is a "functional" C# approach
// NOTE: In C# "maps" are of type Dictionary<Tkey, TValue>
// so our histogram map is of type Dictionary<object, int>
public class HistogramMap {
public Dictionary<object, int> FromList(List<object> list) {
// The "Aggregate" method works like "inject" in many other languages.
return list.Aggregate(
new Dictionary<object, int>(),
(map, obj) => {
// If this is the first time we've seen this obj, set the count to 0
if (!map.ContainsKey(obj)) map[obj] = 0;
// Increment the count
map[obj]++;
// Return the map for the next iteration.
// NOTE: This does NOT return from our "FromList" method
return map;
}
);
}
public static void Main() {
// Create our Histogram Map from a new list
var map = new HistogramMap().FromList(
new List<object>() { 'a', 'b', 'a', 'c', 'b', 'b' }
);
// This just prints the result
System.Console.WriteLine (
string.Join (", ",
// "Select" works like "map" or "collect" in many other languages
map.Select( kvp =>
string.Format("{0} : {1}", kvp.Key, kvp.Value)
).ToArray()
)
);
}
}
new[] {"a","b","a","c","b","b"}
.GroupBy(s => s)
.Select(s => new { Value = s.Key, Count = s.Count() })
.ToList()
.ForEach(e => Console.WriteLine("{0} : {1} ", e.Value, e.Count));
.GroupBy(s => s)
.Select(s => new { Value = s.Key, Count = s.Count() })
.ToList()
.ForEach(e => Console.WriteLine("{0} : {1} ", e.Value, e.Count));
Categorise a list
Given the list
[one, two, three, four, five] produce a map {3:[one, two], 4:[four, five], 5:[three]} which sorts elements into map entries based on their length
perl
@list = qw(one two three four five);
push @{$map{length($_)}}, $_ for (@list);
push @{$map{length($_)}}, $_ for (@list);
erlang
% Imperative Solution
CatList = categorise(List),
CatList = categorise(List),
% Functional (1) Solution
CatList = categorise(List),
CatList = categorise(List),
csharp
using System.Collections.Generic;
using System.Linq;
public class ListCategorizer {
public static void Main() {
var list = new List<string>() { "one", "two", "three", "four", "five" };
var categories = list.GroupBy(el => el.Length)
.ToDictionary( g => g.Key, // key
g => g.ToList() ); // value
}
}
using System.Linq;
public class ListCategorizer {
public static void Main() {
var list = new List<string>() { "one", "two", "three", "four", "five" };
var categories = list.GroupBy(el => el.Length)
.ToDictionary( g => g.Key, // key
g => g.ToList() ); // value
}
}
Perform an action if a condition is true (IF .. THEN)
Given a variable name, if the value is
"Bob", display the string "Hello, Bob!". Perform no action if the name is not equal.
perl
if ($name eq "Bob") {
print "Hello, Bob!"
}
print "Hello, Bob!"
}
print "Hello, Bob!" if $name eq "Bob";
erlang
if (Name == "Bob") -> io:format("Hello, ~s!~n", [Name]) ; true -> false end.
case Name of "Bob" -> io:format("Hello, ~s!~n", [Name]) ; _ -> false end.
Name == "Bob" andalso (begin io:format("Hello, ~s!~n", [Name]), true end).
csharp
if (name == "Bob") Console.WriteLine("Hello, {0}!", name);
Perform different actions depending on a boolean condition (IF .. THEN .. ELSE)
Given a variable age, if the value is greater than 42 display
"You are old", otherwise display "You are young"
perl
if ($age > 42) {
print "You are old"
}
else {
print "You are young"
}
print "You are old"
}
else {
print "You are young"
}
print 'You are ',($age > 42) ? 'old' : 'young';
erlang
if Age > 42 -> io:format("You are old~n") ; true -> io:format("You are young~n") end.
Message = if Age > 42 -> "old" ; true -> "young" end, io:format("You are ~s~n", [Message]).
case Age > 42 of true -> io:format("You are old~n") ; false -> io:format("You are young~n") end.
case Age of _ when Age > 42 -> io:format("You are old~n") ; _ -> io:format("You are young~n") end.
Message = case Age of _ when Age > 42 -> "old" ; _ -> "young" end, io:format("You are ~s~n", [Message]).
Age > 42 andalso (begin io:format("You are old~n"), true end) orelse (begin io:format("You are young~n"), true end).
(fun (X) when X > 42 -> io:format("You are old~n"); (_) -> io:format("You are young~n") end)(Age).
(fun () when Age > 42 -> io:format("You are old~n"); () -> io:format("You are young~n") end)().
io:format("You are ~s~n", [if Age > 42 -> "old" ; true -> "young" end]).
csharp
int age = 41;
if (age > 42)
System.Console.WriteLine("You are old");
else
System.Console.WriteLine("You are young");
if (age > 42)
System.Console.WriteLine("You are old");
else
System.Console.WriteLine("You are young");
Perform different actions depending on several boolean conditions (IF .. THEN .. ELSIF .. ELSE)
perl
if ($age > 84) {
print "You are really ancient";
} elsif ($age > 30) {
print "You are middle-aged";
} else {
print "You are young";
}
print "You are really ancient";
} elsif ($age > 30) {
print "You are middle-aged";
} else {
print "You are young";
}
print 'You are ',
$age > 84 ? 'really ancient!'
: $age > 30 ? 'middle-aged'
: 'young';
$age > 84 ? 'really ancient!'
: $age > 30 ? 'middle-aged'
: 'young';
erlang
if
Age > 84 -> io:format("You are really ancient~n");
Age > 30 -> io:format("You are middle-aged~n");
true -> io:format("You are young~n")
end.
Age > 84 -> io:format("You are really ancient~n");
Age > 30 -> io:format("You are middle-aged~n");
true -> io:format("You are young~n")
end.
case Age of
_ when Age > 84 -> io:format("You are really ancient~n");
_ when Age > 30 -> io:format("You are middle-aged~n");
true -> io:format("You are young~n")
end.
_ when Age > 84 -> io:format("You are really ancient~n");
_ when Age > 30 -> io:format("You are middle-aged~n");
true -> io:format("You are young~n")
end.
csharp
if (age > 84) Console.WriteLine("You are really ancient");
else if (age > 30) Console.WriteLine("You are middle-aged");
else Console.WriteLine("You are young");
else if (age > 30) Console.WriteLine("You are middle-aged");
else Console.WriteLine("You are young");
Console.WriteLine("You are {0}", ((age > 84) ? "really ancient" : (age > 30) ? "middle-aged" : "young"));
Replacing a conditional with many branches with a switch/case statement
Many languages support more compact forms of branching than just if ... then ... else such as switch or case or match. Use such a form to add an appropriate placing suffix to the numbers 1..40, e.g. 1st, 2nd, 3rd, 4th, ..., 11th, 12th, ... 39th, 40th
perl
sub suffix {
my $n = shift;
return 'th' if $n % 100 >= 4 && $n % 100 <= 20;
return 'st' if $n % 10 == 1;
return 'nd' if $n % 10 == 2;
return 'rd' if $n % 10 == 3;
return 'th';
}
foreach my $n (1..40) {
print $n.suffix($n)."\n";
}
my $n = shift;
return 'th' if $n % 100 >= 4 && $n % 100 <= 20;
return 'st' if $n % 10 == 1;
return 'nd' if $n % 10 == 2;
return 'rd' if $n % 10 == 3;
return 'th';
}
foreach my $n (1..40) {
print $n.suffix($n)."\n";
}
erlang
Suffix = case Num of
N when N > 10, N < 20 -> "th";
N when N rem 10 =:= 1 -> "st";
N when N rem 10 =:= 2 -> "nd";
N when N rem 10 =:= 3 -> "rd";
_ -> "th"
end,
io_lib:format("~w~s", [Num, Suffix])
N when N > 10, N < 20 -> "th";
N when N rem 10 =:= 1 -> "st";
N when N rem 10 =:= 2 -> "nd";
N when N rem 10 =:= 3 -> "rd";
_ -> "th"
end,
io_lib:format("~w~s", [Num, Suffix])
csharp
public static string GetOrdinal(int i)
{
if (i > 10 && i < 20) return i.ToString() + "th";
switch (i % 10)
{
case 1:
return i.ToString() + "st";
case 2:
return i.ToString() + "nd";
case 3:
return i.ToString() + "rd";
default:
return i.ToString() + "th";
}
}
{
if (i > 10 && i < 20) return i.ToString() + "th";
switch (i % 10)
{
case 1:
return i.ToString() + "st";
case 2:
return i.ToString() + "nd";
case 3:
return i.ToString() + "rd";
default:
return i.ToString() + "th";
}
}
public static string GetOrdinal(int i)
{
if (i > 10 && i < 20) return i.ToString() + "th";
switch (i % 10)
{
case 1:
return i.ToString() + "st";
break;
case 2:
return i.ToString() + "nd";
break;
case 3:
return i.ToString() + "rd";
break;
default:
return i.ToString() + "th";
break;
}
}
{
if (i > 10 && i < 20) return i.ToString() + "th";
switch (i % 10)
{
case 1:
return i.ToString() + "st";
break;
case 2:
return i.ToString() + "nd";
break;
case 3:
return i.ToString() + "rd";
break;
default:
return i.ToString() + "th";
break;
}
}
Perform an action multiple times based on a boolean condition, checked before the first action (WHILE .. DO)
Starting with a variable x=1, Print the sequence
"1,2,4,8,16,32,64,128," by doubling x and checking that x is less than 150.
perl
my $x = 1;
while($x < 150) {
print $x, ",";
$x *=2
}
while($x < 150) {
print $x, ",";
$x *=2
}
erlang
X = 1, print_while_X_less_150(X).
Pred = fun (X) -> X < 150 end,
Action = fun (X) -> io:format("~B,", [X]), X * 2 end,
X = 1,
while_do(Pred, Action, X).
Action = fun (X) -> io:format("~B,", [X]), X * 2 end,
X = 1,
while_do(Pred, Action, X).
csharp
int x = 1;
while (x < 150)
{
x *= 2;
Console.Write("{0},", x);
}
while (x < 150)
{
x *= 2;
Console.Write("{0},", x);
}
Perform an action multiple times based on a boolean condition, checked after the first action (DO .. WHILE)
Simulate rolling a die until you get a six. Produce random numbers, printing them until a six is rolled. An example output might be
"4,2,1,2,6"
perl
do {
my $number = int(rand(6)+1);
print $number;
print ',' if ($number != 6);
} while ($number != 6);
my $number = int(rand(6)+1);
print $number;
print ',' if ($number != 6);
} while ($number != 6);
erlang
Pred = fun (DiceRoll) -> DiceRoll =/= 6 end,
Action = fun (DiceRoll) -> io:format("~B,", [DiceRoll]), dice_roll() end,
do_while(Pred, Action, dice_roll()).
Action = fun (DiceRoll) -> io:format("~B,", [DiceRoll]), dice_roll() end,
do_while(Pred, Action, dice_roll()).
-module(dice).
-export([start/0]).
start() ->
roll(dice_roll()).
roll(6) ->
io:format("6~n", []);
roll(N) ->
io:format("~B,", [N]),
roll(dice_roll()).
dice_roll() -> random:uniform(6).
-export([start/0]).
start() ->
roll(dice_roll()).
roll(6) ->
io:format("6~n", []);
roll(N) ->
io:format("~B,", [N]),
roll(dice_roll()).
dice_roll() -> random:uniform(6).
csharp
System.Random die = new System.Random();
int roll;
do
{
roll = die.Next(1, 6);
Console.Write(roll);
if (roll < 6) Console.Write(",");
}
while (roll != 6);
int roll;
do
{
roll = die.Next(1, 6);
Console.Write(roll);
if (roll < 6) Console.Write(",");
}
while (roll != 6);
Perform an action a fixed number of times (FOR)
Display the string
"Hello" five times like "HelloHelloHelloHelloHello"
perl
print "Hello" x 5
print "Hello" for (1..5)
erlang
dotimes(5, fun () -> io:format("Hello") end).
lists:foreach(fun (_) -> io:format("Hello") end, lists:seq(1, 5)).
csharp
string text = "Hello";
for (int i = 0; i < 5; i++)
{
Console.Write(text);
}
for (int i = 0; i < 5; i++)
{
Console.Write(text);
}
Perform an action a fixed number of times with a counter
Display the string
"10 .. 9 .. 8 .. 7 .. 6 .. 5 .. 4 .. 3 .. 2 .. 1 .. Liftoff!"
perl
for (my $i = 10; $i > 0; $i--) {
print "$i .. ";
}
print "Liftoff!";
print "$i .. ";
}
print "Liftoff!";
print "$_ .. " for reverse 1..10;
print "Liftoff!";
print "Liftoff!";
erlang
fromto(10, 1, -1, fun (X) -> io:format("~B .. ", [X]) end), io:format("Liftoff!~n").
lists:foreach(fun (X) -> io:format("~B .. ", [X]) end, lists:seq(10, 1, -1)), io:format("Liftoff!~n").
csharp
for (int i = 10; i > 0; i--)
{
Console.Write("{0} .. ", i);
}
Console.WriteLine("Liftoff!");
{
Console.Write("{0} .. ", i);
}
Console.WriteLine("Liftoff!");
Read the contents of a file into a string
perl
@file = read()
open(my $fh, '<', $path) or die "can't open $path: $!";
$string = do { local $/; <$fh> };
close $fh;
$string = do { local $/; <$fh> };
close $fh;
erlang
Text = readfile("Solution607.erl"),
Text = readfile("Solution608.erl"),
csharp
string contents = System.IO.File.ReadAllText("filename.txt");
Process a file one line at a time
Open the source file to your solution and print each line in the file, prefixed by the line number, like:
1> First line of file
2> Second line of file
3> Third line of file
1> First line of file
2> Second line of file
3> Third line of file
perl
open(my $fh, '<', $path) or die "can't open $path: $!";
$c = 1;
print $c++ . "> $_" for (<$fh>);
close $fh;
$c = 1;
print $c++ . "> $_" for (<$fh>);
close $fh;
open my $fh, '<', $path or die "Can't open $path: $!";
while (<$fh>) {
print "$.> $_";
}
while (<$fh>) {
print "$.> $_";
}
erlang
Reader = fun (IODevice) -> io:get_line(IODevice, "") end,
Worker = fun (Line, N) -> io:format("~B> ~s", [N, Line]), N + 1 end,
while_not_eof("Solution609.erl", Reader, Worker, 1).
Worker = fun (Line, N) -> io:format("~B> ~s", [N, Line]), N + 1 end,
while_not_eof("Solution609.erl", Reader, Worker, 1).
Reader = fun (Filename) -> {ok, Contents} = file:read_file(Filename), Contents end,
Transformer = fun (Line, N) -> string:concat(string:concat(integer_to_list(N), "> "), Line) end,
Printer = fun (Line) -> io:format("~s~n", [Line]) end,
Lines = string:tokens(binary_to_list(Reader("Solution610.erl")), "\n"),
NewLines = lists:zipwith(Transformer, Lines, lists:seq(1, length(Lines))),
lists:foreach(Printer, NewLines).
Transformer = fun (Line, N) -> string:concat(string:concat(integer_to_list(N), "> "), Line) end,
Printer = fun (Line) -> io:format("~s~n", [Line]) end,
Lines = string:tokens(binary_to_list(Reader("Solution610.erl")), "\n"),
NewLines = lists:zipwith(Transformer, Lines, lists:seq(1, length(Lines))),
lists:foreach(Printer, NewLines).
csharp
int counter = 0;
// If the file is large, you would want to buffer this instead of reading everything at once
foreach (string line in System.IO.File.ReadAllLines("filename.txt"))
{
Console.WriteLine("{0}> {1}", ++counter, line);
}
// If the file is large, you would want to buffer this instead of reading everything at once
foreach (string line in System.IO.File.ReadAllLines("filename.txt"))
{
Console.WriteLine("{0}> {1}", ++counter, line);
}
Write a string to a file
perl
open(my $fh, '>', $path) or die "can't open $path: $!";
print $fh "This line overwites file contents!";
close $fh;
print $fh "This line overwites file contents!";
close $fh;
erlang
Line = "This line overwites file contents!\n",
{ok, IODevice} = file:open("test.txt", [write]), file:write(IODevice, Line), file:close(IODevice).
{ok, IODevice} = file:open("test.txt", [write]), file:write(IODevice, Line), file:close(IODevice).
csharp
System.IO.File.WriteAllText("filename.txt", "Some text to write to the file");
Append to a file
perl
open(my $fh, '>>', $path) or die "can't open $path: $!";
print $fh "This line is appended to the file!";
close $fh;
print $fh "This line is appended to the file!";
close $fh;
erlang
Line = "This line appended to file!\n",
{ok, IODevice} = file:open("test.txt", [append]), file:write(IODevice, Line), file:close(IODevice).
{ok, IODevice} = file:open("test.txt", [append]), file:write(IODevice, Line), file:close(IODevice).
csharp
System.IO.File.AppendAllText("filename.txt", "Some text to append to the file");
Process each file in a directory
perl
use File::Glob;
for (<*>) {
process_file($_) if (-f);
}
for (<*>) {
process_file($_) if (-f);
}
erlang
% File basenames only - many tasks require absolute paths to work
lists:foreach(fun (FileOrDirPath) -> Worker(FileOrDirPath) end, file:list_dir(Directory)).
lists:foreach(fun (FileOrDirPath) -> Worker(FileOrDirPath) end, file:list_dir(Directory)).
% Absolute paths provided - will accomodate most tasks
lists:foreach(fun (FileOrDirPath) -> Worker(FileOrDirPath) end, list_dir_path(Directory)).
lists:foreach(fun (FileOrDirPath) -> Worker(FileOrDirPath) end, list_dir_path(Directory)).
csharp
foreach (string filename in System.IO.Directory.GetFiles(directory)) ProcessFile(filename);
Process each file in a directory recursively
perl
use File::Glob;
process_directory(".");
sub process_directory {
my $dir = shift;
for my $file (<$dir/*>) {
next unless (-r $file);
if (-f $file) {
process_file($file);
} elsif (-d $file) {
process_directory($file);
}
}
}
process_directory(".");
sub process_directory {
my $dir = shift;
for my $file (<$dir/*>) {
next unless (-r $file);
if (-f $file) {
process_file($file);
} elsif (-d $file) {
process_directory($file);
}
}
}
use File::Find ();
# Traverse desired filesystems
sub process_directory {
my $directory = shift;
File::Find::find({wanted => \&wanted}, $directory);
}
sub wanted {
process_file( $File::Find::name );
}
# Traverse desired filesystems
sub process_directory {
my $directory = shift;
File::Find::find({wanted => \&wanted}, $directory);
}
sub wanted {
process_file( $File::Find::name );
}
erlang
filelib:fold_files(Directory, ".*", true, fun (FileOrDirPath, Acc) -> Worker(FileOrDirPath), Acc end, []).
process_dir(Directory, Worker).
Parse a date and time from a string
Given the string
"2008-05-06 13:29", parse it as a date representing 6th March, 2008 1:29:00pm in the local time zone.
perl
#! /usr/bin/perl
# -*- Mode: CPerl -*-
use strict;
use POSIX;
# Given the string "2008-05-06 13:29", parse it as a date
# representing 6th March, 2008 1:29:00pm in the local time zone.
my $ds = "2008-05-06 13:29";
my $y;
my $m;
my $d;
my $hr;
my $mn;
print "Original: ",$ds,"\n";
if ( $ds =~ /(\d{4})-(\d{2})-(\d{2})\s+(\d{2}):(\d{2})/ ){
$y = $1 - 1900;
$m = $2;
$d = $3;
$hr = $4;
$mn = $5;
printf "Nominal: %s\n",
strftime("%e %B, %Y %l:%M:%S%P",0, $mn , $hr, $d, $m,$y);
my $eth = "";
if ( $d == 1 ){
$eth = "st";
} elsif ( $d == 2 ){
$eth = "nd";
} elsif ( $d == 3 ){
$eth = "rd";
} else {
$eth = "th";
}
printf "As required: %d%s %s\n",$d,$eth,
strftime("%B, %Y %l:%M:%S%P",0, $mn , $hr, $d, $m,$y);
}
#eos
# -*- Mode: CPerl -*-
use strict;
use POSIX;
# Given the string "2008-05-06 13:29", parse it as a date
# representing 6th March, 2008 1:29:00pm in the local time zone.
my $ds = "2008-05-06 13:29";
my $y;
my $m;
my $d;
my $hr;
my $mn;
print "Original: ",$ds,"\n";
if ( $ds =~ /(\d{4})-(\d{2})-(\d{2})\s+(\d{2}):(\d{2})/ ){
$y = $1 - 1900;
$m = $2;
$d = $3;
$hr = $4;
$mn = $5;
printf "Nominal: %s\n",
strftime("%e %B, %Y %l:%M:%S%P",0, $mn , $hr, $d, $m,$y);
my $eth = "";
if ( $d == 1 ){
$eth = "st";
} elsif ( $d == 2 ){
$eth = "nd";
} elsif ( $d == 3 ){
$eth = "rd";
} else {
$eth = "th";
}
printf "As required: %d%s %s\n",$d,$eth,
strftime("%B, %Y %l:%M:%S%P",0, $mn , $hr, $d, $m,$y);
}
#eos
# Shurely you mean 6th MAY? If not, oh well
use Time::Piece;
my $dt_str = '2008-05-06 13:29';
my $tp = Time::Piece->strptime( $dt_str, '%Y-%m-%d %H:%M');
print $tp,"\n";
use Time::Piece;
my $dt_str = '2008-05-06 13:29';
my $tp = Time::Piece->strptime( $dt_str, '%Y-%m-%d %H:%M');
print $tp,"\n";
erlang
% AFAIK, no datetime-parsing library exists; 'parse_to_datetime' is a simplistic, problem-specific hack
LocalDateTime = erlang:universaltime_to_localtime(parse_to_datetime("2008-05-06 13:29:34")),
LocalDateTime = erlang:universaltime_to_localtime(parse_to_datetime("2008-05-06 13:29:34")),
csharp
DateTime parsedDate = DateTime.Parse("2008-05-06 13:29");
// Ideally, you would catch the potential FormatException or use DateTime.TryParse in production code.
// Ideally, you would catch the potential FormatException or use DateTime.TryParse in production code.
Display information about a date
Display the day of month, day of year, month name and day name of the day 8 days from now.
perl
#! /usr/bin/perl
# -*- Mode: CPerl -*-
use strict;
use Date::Calc qw(:all);
my $days_in_future = $ARGV[0];
$days_in_future = 8 unless $days_in_future;
my ($year,$month,$day, $hour,$min,$sec, $doy,$dow,$dst) = Localtime();
my ($fyear,$fmonth,$fday) = Add_Delta_Days($year,$month,$day,$days_in_future);
printf "Now: %d-%2.2d-%2.2d %2.2d:%2.2d:%2.2d\n",
$year,$month,$day,$hour,$min,$sec;
printf "Then: %d-%2.2d-%2.2d %2.2d:%2.2d:%2.2d\n",
$fyear,$fmonth,$fday,$hour,$min,$sec;
printf "Then: day of month: %d\n",$fday;
printf "Then: day of year: %d\n",Day_of_Year($fyear,$fmonth,$fday);
printf "Then: day of name: %s\n",
Day_of_Week_to_Text(Day_of_Week($fyear,$fmonth,$fday));
printf "Then: month name: %s\n",Month_to_Text($fmonth);
#eos
# -*- Mode: CPerl -*-
use strict;
use Date::Calc qw(:all);
my $days_in_future = $ARGV[0];
$days_in_future = 8 unless $days_in_future;
my ($year,$month,$day, $hour,$min,$sec, $doy,$dow,$dst) = Localtime();
my ($fyear,$fmonth,$fday) = Add_Delta_Days($year,$month,$day,$days_in_future);
printf "Now: %d-%2.2d-%2.2d %2.2d:%2.2d:%2.2d\n",
$year,$month,$day,$hour,$min,$sec;
printf "Then: %d-%2.2d-%2.2d %2.2d:%2.2d:%2.2d\n",
$fyear,$fmonth,$fday,$hour,$min,$sec;
printf "Then: day of month: %d\n",$fday;
printf "Then: day of year: %d\n",Day_of_Year($fyear,$fmonth,$fday);
printf "Then: day of name: %s\n",
Day_of_Week_to_Text(Day_of_Week($fyear,$fmonth,$fday));
printf "Then: month name: %s\n",Month_to_Text($fmonth);
#eos
use Time::Piece;
use Time::Seconds;
my $t = localtime;
my $t_8 = $t + (ONE_DAY * 8);
printf "Now: %d, %d, %s, %s\n",
$t->day_of_month, $t->day_of_year, $t->fullmonth, $t->fullday;
printf "Then: %d, %d, %s, %s\n",
$t_8->day_of_month, $t_8->day_of_year, $t_8->fullmonth, $t_8->fullday;
use Time::Seconds;
my $t = localtime;
my $t_8 = $t + (ONE_DAY * 8);
printf "Now: %d, %d, %s, %s\n",
$t->day_of_month, $t->day_of_year, $t->fullmonth, $t->fullday;
printf "Then: %d, %d, %s, %s\n",
$t_8->day_of_month, $t_8->day_of_year, $t_8->fullmonth, $t_8->fullday;
csharp
DateTime date = DateTime.Today.AddDays(8);
Console.WriteLine("Day of month: " + date.Day);
Console.WriteLine("Day of year: " + date.DayOfYear);
Console.WriteLine("Month name: " + date.ToString("MMMM"));
Console.WriteLine("Day name: " + date.ToString("dddd"));
// The two ToString calls will use the current locale.
// To get localised month and day names, see http://msdn.microsoft.com/en-us/library/8tfzyc64.aspx
Console.WriteLine("Day of month: " + date.Day);
Console.WriteLine("Day of year: " + date.DayOfYear);
Console.WriteLine("Month name: " + date.ToString("MMMM"));
Console.WriteLine("Day name: " + date.ToString("dddd"));
// The two ToString calls will use the current locale.
// To get localised month and day names, see http://msdn.microsoft.com/en-us/library/8tfzyc64.aspx
Display a date in different locales
Display a language/locale friendly version of New Year's Day for 2009 for several languages/locales. E.g. for languages English, French, German, Italian, Dutch the output might be something like:
Thursday, January 1, 2009
jeudi 1 janvier 2009
giovedì 1 gennaio 2009
Donnerstag, 1. Januar 2009
donderdag 1 januari 2009
(Indicate in comments where possible if any language specific or operating system configuration needs to be in place.)
Thursday, January 1, 2009
jeudi 1 janvier 2009
giovedì 1 gennaio 2009
Donnerstag, 1. Januar 2009
donderdag 1 januari 2009
(Indicate in comments where possible if any language specific or operating system configuration needs to be in place.)
perl
#!/usr/bin/perl
use warnings;
use strict;
use locale;
use POSIX qw(strftime);
use Time::Local;
my $date=timegm(0,0,0, 1,0,101); #00:00:00 01/01/2001
my $str_time = strftime "%c", gmtime;
print "Date: $str_time\n";
use warnings;
use strict;
use locale;
use POSIX qw(strftime);
use Time::Local;
my $date=timegm(0,0,0, 1,0,101); #00:00:00 01/01/2001
my $str_time = strftime "%c", gmtime;
print "Date: $str_time\n";
csharp
using System.Globalization;
DateTime newYearsDay = new DateTime(2009, 1, 1);
CultureInfo[] locales = {
CultureInfo.CreateSpecificCulture("en-US"),
CultureInfo.CreateSpecificCulture("fr-FR"),
CultureInfo.CreateSpecificCulture("de-DE"),
CultureInfo.CreateSpecificCulture("it-IT"),
CultureInfo.CreateSpecificCulture("nl-NL")
};
foreach (CultureInfo locale in locales)
{
Console.WriteLine(newYearsDay.ToString("D", locale));
}
DateTime newYearsDay = new DateTime(2009, 1, 1);
CultureInfo[] locales = {
CultureInfo.CreateSpecificCulture("en-US"),
CultureInfo.CreateSpecificCulture("fr-FR"),
CultureInfo.CreateSpecificCulture("de-DE"),
CultureInfo.CreateSpecificCulture("it-IT"),
CultureInfo.CreateSpecificCulture("nl-NL")
};
foreach (CultureInfo locale in locales)
{
Console.WriteLine(newYearsDay.ToString("D", locale));
}
Display the current date and time
Create a Date object representing the current date and time. Print it out.
If you can also do this without creating a Date object you can show that too.
If you can also do this without creating a Date object you can show that too.
perl
use Class::Date;
my $date = Class::Date->now();
print $date->string()."\n";
print localtime()."\n";
my $date = Class::Date->now();
print $date->string()."\n";
print localtime()."\n";
use Time::Piece ();
# Date object
my $date = Time::Piece::localtime;
print "$date\n";
# no object
print scalar(localtime),"\n";
# Date object
my $date = Time::Piece::localtime;
print "$date\n";
# no object
print scalar(localtime),"\n";
erlang
io:format("~p~n", [calendar:local_time()])
csharp
// Creating a variable first:
DateTime now = DateTime.Now;
Console.WriteLine(now);
// Without creating a variable:
Console.WriteLine(DateTime.Now);
DateTime now = DateTime.Now;
Console.WriteLine(now);
// Without creating a variable:
Console.WriteLine(DateTime.Now);
Define a class
Declare a class named Greeter that takes a string on creation and greets using this string if you call the
"greet" method.
perl
{ package Greeter;
sub new {
my $self = {};
my $type = shift;
$self->{'whom'} = shift;
bless $self, $type;
}
sub greet {
my $self = shift;
print "Hello " . $self->{'whom'} . "!\n";
}
}
my $greeter = Greeter->new("world");
$greeter->greet();
sub new {
my $self = {};
my $type = shift;
$self->{'whom'} = shift;
bless $self, $type;
}
sub greet {
my $self = shift;
print "Hello " . $self->{'whom'} . "!\n";
}
}
my $greeter = Greeter->new("world");
$greeter->greet();
{
package Greeter;
sub new {
my $class = shift;
my $whom = shift or die 'Need a name to greet';
bless \$whom, $class;
}
sub greet {
my $self = shift;
print "Hello $$self!\n";
}
}
my $greeter = Greeter->new("Bob");
$greeter->greet();
package Greeter;
sub new {
my $class = shift;
my $whom = shift or die 'Need a name to greet';
bless \$whom, $class;
}
sub greet {
my $self = shift;
print "Hello $$self!\n";
}
}
my $greeter = Greeter->new("Bob");
$greeter->greet();
erlang
Greeter = make_greeter("world!"),
Greeter(greet).
Greeter(greet).
csharp
using System;
class Greeter
{
private string name {get;set;}
public void Greet(){
Console.WriteLine("Hello, {0}",name);
}
public Greeter(string name){
this.name = name;
}
}
class Test
{
static void Main()
{
new Greeter("Dante").Greet();
}
}
class Greeter
{
private string name {get;set;}
public void Greet(){
Console.WriteLine("Hello, {0}",name);
}
public Greeter(string name){
this.name = name;
}
}
class Test
{
static void Main()
{
new Greeter("Dante").Greet();
}
}
Instantiate object with mutable state
Reimplement the Greeter class so that the
For example, if the greetee is changed to
Hello, Tommy!
The getter would then be used to display the line:
I have just greeted Tommy.
'whom' property or data member remains private but is mutable, and is provided with getter and setter methods. Invoke the setter to change the greetee, invoke 'greet', then use the getter in displaying the line, "I have just greeted {whom}.".
For example, if the greetee is changed to
'Tommy' using the setter, the 'greet' method would display:
Hello, Tommy!
The getter would then be used to display the line:
I have just greeted Tommy.
perl
package Greeter;
sub new {
my ($class, $whom) = @_;
bless {whom => $whom}, $class;
}
sub whom {
my ($self, $whom) = @_;
if ($whom) { $self->{whom} = $whom; }
else { return $self->{whom} }
}
sub greet {
my ($self) = @_;
my $whom = $self->{whom};
print "Hello, $whom!\n";
}
package main;
my $g = new Greeter ("world");
$g->greet;
$g->whom("Tommy");
$g->greet;
print "I have just greeted " . $g->whom . "\n";
sub new {
my ($class, $whom) = @_;
bless {whom => $whom}, $class;
}
sub whom {
my ($self, $whom) = @_;
if ($whom) { $self->{whom} = $whom; }
else { return $self->{whom} }
}
sub greet {
my ($self) = @_;
my $whom = $self->{whom};
print "Hello, $whom!\n";
}
package main;
my $g = new Greeter ("world");
$g->greet;
$g->whom("Tommy");
$g->greet;
print "I have just greeted " . $g->whom . "\n";
csharp
class Greeter
{
public string Name {get;set;}
public void Greet(){
Console.WriteLine("Hello, {0}",Name);
}
public Greeter(string name){
this.Name = name;
}
// Driver
public static void Main()
{
var g = new Greeter("Dante");
g.Name = "Tommy";
g.Greet();
Console.Write("I have just greated {0}", g.Name);
}
}
{
public string Name {get;set;}
public void Greet(){
Console.WriteLine("Hello, {0}",Name);
}
public Greeter(string name){
this.Name = name;
}
// Driver
public static void Main()
{
var g = new Greeter("Dante");
g.Name = "Tommy";
g.Greet();
Console.Write("I have just greated {0}", g.Name);
}
}
Implement Inheritance Heirarchy
Implement a Shape abstract class which will form the base of an inheritance hierarchy that models 2D geometric shapes. It will have:
* A non-mutable
* A
* A
* A non-mutable
'name' property or data member set by derived or descendant classes at construction time
* A
'area' method intended to be overridden by derived or descendant classes ( double precision floating point return value)
* A
'print' method (also for overriding) will display the shape's name, area, and all shape-specific values
Two derived or descendant classes will be created:
* Circle -> Constructor requires a 'radius' argument, and a 'circumference' method to be implemented
* Rectangle -> Constructor requires 'length' and 'breadth' arguments, and a 'perimeter' method to be implemented
Instantiate an object of each class, and invoke each objects 'print' method to show relevant details.
perl
package Shapes;
use MooseX::Declare;
class Shape {
use MooseX::ABC;
requires qw/area print/;
has 'name' => (is => 'ro', isa => 'Str', default => '', required => 0, init_arg => undef );
}
class Circle extends Shape {
use constant PI => 4 * atan2(1, 1);
has '+name' => ( default => 'circle' );
has 'radius' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'r' );
sub area { PI * ( $_[0]->radius ** 2 ) }
sub circumference { 2 * PI * ( $_[0]->radius ** 2 ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name radius area circumference/;
I am a '%s' with
Radius: %.2f
Area: %.2f
Circumference: %.2f
END_OF_BLOCK
}
}
class Rectangle extends Shape {
has '+name' => ( default => 'rectangle' );
has 'length' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'l' );
has 'breadth' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'b' );
sub area { $_[0]->length * $_[0]->breadth }
sub perimeter { 2 * ( $_[0]->length + $_[0]->breadth ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name length breadth area perimeter/;
I am a '%s' with
Length, Width: %.2f, %.2f
Area: %.2f
Perimeter: %.2f
END_OF_BLOCK
}
}
1;
package main;
my @shapes = ( Circle->new( r => 4.2 ), Rectangle->new(l => 2.7, b => 3.1),
Rectangle->new(l => 6.2, b => 2.6), Circle->new( r => 17.3) );
$_->print for @shapes;
use MooseX::Declare;
class Shape {
use MooseX::ABC;
requires qw/area print/;
has 'name' => (is => 'ro', isa => 'Str', default => '', required => 0, init_arg => undef );
}
class Circle extends Shape {
use constant PI => 4 * atan2(1, 1);
has '+name' => ( default => 'circle' );
has 'radius' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'r' );
sub area { PI * ( $_[0]->radius ** 2 ) }
sub circumference { 2 * PI * ( $_[0]->radius ** 2 ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name radius area circumference/;
I am a '%s' with
Radius: %.2f
Area: %.2f
Circumference: %.2f
END_OF_BLOCK
}
}
class Rectangle extends Shape {
has '+name' => ( default => 'rectangle' );
has 'length' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'l' );
has 'breadth' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'b' );
sub area { $_[0]->length * $_[0]->breadth }
sub perimeter { 2 * ( $_[0]->length + $_[0]->breadth ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name length breadth area perimeter/;
I am a '%s' with
Length, Width: %.2f, %.2f
Area: %.2f
Perimeter: %.2f
END_OF_BLOCK
}
}
1;
package main;
my @shapes = ( Circle->new( r => 4.2 ), Rectangle->new(l => 2.7, b => 3.1),
Rectangle->new(l => 6.2, b => 2.6), Circle->new( r => 17.3) );
$_->print for @shapes;
{
package Shapes;
sub new {
my $class = shift;
die 'Invalid parameters' if (@_ % 2);
my %parameters = @_;
die 'Missing name' unless defined $parameters{name};
bless \%parameters, $class
}
sub area {
die
'area() method must be implemented by ',__PACKAGE__.' subclasses';
}
sub print {
my $self = shift;
printf "Name: \t%s\n", $self->{name};
printf "Area: \t%.2f\n", $self->area();
}
}
{
package Circle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
use Math::Trig;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Circle', @_);
die 'Missing radius' unless defined($self->{radius});
die 'Invalid radius (not a number)'
unless looks_like_number($self->{radius});
$self
}
sub area {
my $self = shift;
pi * ($self->{radius} ** 2)
}
sub circumference {
my $self = shift;
2 * pi * $self->{radius};
}
sub print {
my $self = shift;
$self->SUPER::print;
printf "Circumference: \t%.2f\n", $self->circumference;
}
}
{
package Rectangle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Rectangle', @_);
do {
die "Missing $_" unless defined($self->{$_});
die "Invalid $_" unless looks_like_number($self->{$_});
} for qw/length breadth/;
$self;
}
sub area {
my $self = shift;
$self->{length} * $self->{breadth}
}
sub print {
my $self = shift;
$self->SUPER::print();
do {
printf ucfirst($_).": \t%.2f\n", $self->{$_}
} for qw/length breadth/;
}
}
package main;
my @shapes = ( Circle->new( radius => 4.2 ),
Rectangle->new(length => 2.7, breadth => 3.1),
Rectangle->new(length => 6.2, breadth => 2.6),
Circle->new( radius => 17.3) );
$_->print for @shapes;
package Shapes;
sub new {
my $class = shift;
die 'Invalid parameters' if (@_ % 2);
my %parameters = @_;
die 'Missing name' unless defined $parameters{name};
bless \%parameters, $class
}
sub area {
die
'area() method must be implemented by ',__PACKAGE__.' subclasses';
}
sub print {
my $self = shift;
printf "Name: \t%s\n", $self->{name};
printf "Area: \t%.2f\n", $self->area();
}
}
{
package Circle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
use Math::Trig;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Circle', @_);
die 'Missing radius' unless defined($self->{radius});
die 'Invalid radius (not a number)'
unless looks_like_number($self->{radius});
$self
}
sub area {
my $self = shift;
pi * ($self->{radius} ** 2)
}
sub circumference {
my $self = shift;
2 * pi * $self->{radius};
}
sub print {
my $self = shift;
$self->SUPER::print;
printf "Circumference: \t%.2f\n", $self->circumference;
}
}
{
package Rectangle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Rectangle', @_);
do {
die "Missing $_" unless defined($self->{$_});
die "Invalid $_" unless looks_like_number($self->{$_});
} for qw/length breadth/;
$self;
}
sub area {
my $self = shift;
$self->{length} * $self->{breadth}
}
sub print {
my $self = shift;
$self->SUPER::print();
do {
printf ucfirst($_).": \t%.2f\n", $self->{$_}
} for qw/length breadth/;
}
}
package main;
my @shapes = ( Circle->new( radius => 4.2 ),
Rectangle->new(length => 2.7, breadth => 3.1),
Rectangle->new(length => 6.2, breadth => 2.6),
Circle->new( radius => 17.3) );
$_->print for @shapes;
csharp
// While abstract classes do exist in C#, it is most common to use
// an interface in this type of situation.
// It is a common idiom to prefix interface names with an I
public interface IShape {
string Name { get; }
double Area { get; }
void Print();
}
public class Circle : IShape {
private double Radius { get; set; }
public Circle(double radius) {
Name = "Circle";
Radius = radius;
}
public string Name { get; private set; }
public double Area {
get {
return Math.PI * Radius * Radius;
}
}
public double Circumference {
get {
return Math.PI * (Radius + Radius);
}
}
public void Print() {
Console.WriteLine( " Name: {0}\n Area: {1}\n Circumference: {2}\n Radius: {3}",
this.Name,
this.Area,
this.Circumference,
this.Radius
);
}
}
public class Rectangle : IShape {
private double Length { get; set; }
private double Breadth { get; set; }
public Rectangle(double length, double breadth) {
Name = "Rectangle";
Length = length;
Breadth = breadth;
}
public string Name { get; private set; }
public double Area {
get {
return Length * Breadth;
}
}
public double Perimeter {
get {
return (Length * 2) + (Breadth * 2 );
}
}
public void Print() {
Console.WriteLine( " Name: {0}\n Area: {1}\n Perimeter: {2}\n Length: {3}\n Breadth: {4}",
this.Name,
this.Area,
this.Perimeter,
this.Length,
this.Breadth
);
}
}
// Driver
public class InheritanceHeirarchy {
public static void _Main() {
var c = new Circle(2.1);
c.Print();
Console.WriteLine();
var r = new Rectangle(2.2, 3.3);
r.Print();
}
}
// an interface in this type of situation.
// It is a common idiom to prefix interface names with an I
public interface IShape {
string Name { get; }
double Area { get; }
void Print();
}
public class Circle : IShape {
private double Radius { get; set; }
public Circle(double radius) {
Name = "Circle";
Radius = radius;
}
public string Name { get; private set; }
public double Area {
get {
return Math.PI * Radius * Radius;
}
}
public double Circumference {
get {
return Math.PI * (Radius + Radius);
}
}
public void Print() {
Console.WriteLine( " Name: {0}\n Area: {1}\n Circumference: {2}\n Radius: {3}",
this.Name,
this.Area,
this.Circumference,
this.Radius
);
}
}
public class Rectangle : IShape {
private double Length { get; set; }
private double Breadth { get; set; }
public Rectangle(double length, double breadth) {
Name = "Rectangle";
Length = length;
Breadth = breadth;
}
public string Name { get; private set; }
public double Area {
get {
return Length * Breadth;
}
}
public double Perimeter {
get {
return (Length * 2) + (Breadth * 2 );
}
}
public void Print() {
Console.WriteLine( " Name: {0}\n Area: {1}\n Perimeter: {2}\n Length: {3}\n Breadth: {4}",
this.Name,
this.Area,
this.Perimeter,
this.Length,
this.Breadth
);
}
}
// Driver
public class InheritanceHeirarchy {
public static void _Main() {
var c = new Circle(2.1);
c.Print();
Console.WriteLine();
var r = new Rectangle(2.2, 3.3);
r.Print();
}
}
Implement and use an Interface
Create a Serializable interface consisting of
* Accept a stream or handle or descriptor argument for the source or destination
* Save to destination or restore from source the properties or data members of the implementing class (restrict yourself to the primitive types
Next, create a Person class which has
'save' and 'restore' methods, each of which:
* Accept a stream or handle or descriptor argument for the source or destination
* Save to destination or restore from source the properties or data members of the implementing class (restrict yourself to the primitive types
'int' and 'string')
Next, create a Person class which has
'name' and 'age' properties or data members and implements this interface. Instantiate a Person object, save it to a serial stream, and instantiate a new Person object by restoring it from the serial stream.
perl
package Person;
use Moose;
use MooseX::Storage;
with Storage('format' => 'JSON', 'io' => 'File');
has 'name' => (is => 'rw', isa => 'Str');
has 'age' => (is => 'rw', isa => 'Int');
1;
Person->new( name => 'David B.', age => 28)->store('person.json');
my $p = Person->load('person.json');
use Moose;
use MooseX::Storage;
with Storage('format' => 'JSON', 'io' => 'File');
has 'name' => (is => 'rw', isa => 'Str');
has 'age' => (is => 'rw', isa => 'Int');
1;
Person->new( name => 'David B.', age => 28)->store('person.json');
my $p = Person->load('person.json');
{
package Serializable;
use Role::Basic;
use Storable qw'store_fd retrieve_fd';
use Scalar::Util 'blessed';
use IO::Handle;
use Carp;
sub save {
my $self = shift;
my $fd = shift or croak 'Needs target file handle';
$DB::single = (1);
store_fd($self, $fd);
}
sub restore {
my $class = shift;
my $fd = shift or croak 'Needs source file handle';
my $self = retrieve_fd( $fd );
bless $self, $class
}
}
{
package Person;
use Role::Basic 'with';
use Scalar::Util 'looks_like_number';
use Carp;
with 'Serializable';
sub new {
my $class = shift;
croak 'Invalid parameters' if (@_ % 2);
%parameters = @_;
do {
croak "Missing $_" unless defined $parameters{$_}
} for qw/name age/;
croak 'Invalid age' unless looks_like_number($parameters{age});
bless \%parameters, $class
}
sub name {
$self{name}
}
sub age {
$self{age}
}
}
use IO::Handle;
my $p1 = Person->new(age => 42, name => 'Milly Fogg');
open my $fh, '+>', 'person.store';
$p1->save( $fh );
seek $fh, 0, SEEK_SET;
my $p2 = Person->restore( $fh );
package Serializable;
use Role::Basic;
use Storable qw'store_fd retrieve_fd';
use Scalar::Util 'blessed';
use IO::Handle;
use Carp;
sub save {
my $self = shift;
my $fd = shift or croak 'Needs target file handle';
$DB::single = (1);
store_fd($self, $fd);
}
sub restore {
my $class = shift;
my $fd = shift or croak 'Needs source file handle';
my $self = retrieve_fd( $fd );
bless $self, $class
}
}
{
package Person;
use Role::Basic 'with';
use Scalar::Util 'looks_like_number';
use Carp;
with 'Serializable';
sub new {
my $class = shift;
croak 'Invalid parameters' if (@_ % 2);
%parameters = @_;
do {
croak "Missing $_" unless defined $parameters{$_}
} for qw/name age/;
croak 'Invalid age' unless looks_like_number($parameters{age});
bless \%parameters, $class
}
sub name {
$self{name}
}
sub age {
$self{age}
}
}
use IO::Handle;
my $p1 = Person->new(age => 42, name => 'Milly Fogg');
open my $fh, '+>', 'person.store';
$p1->save( $fh );
seek $fh, 0, SEEK_SET;
my $p2 = Person->restore( $fh );
Check your language appears on the langref.org site
Your language name should appear within the HTML found at the http:
//langreg.org main page.
perl
# requires libwww-perl
use LWP::Simple;
if (grep /perl/, get('http://langref.org/')) {
print 'perl appears on langref.org';
} else {
print 'perl does not appear on langref.org';
}
use LWP::Simple;
if (grep /perl/, get('http://langref.org/')) {
print 'perl appears on langref.org';
} else {
print 'perl does not appear on langref.org';
}
erlang
URL = "http://langref.org/", Language = "erlang", Regexp = ".*" ++ URL ++ Language ++ ".*",
case http:request(URL) of
{ok, {_, _, Body}} ->
case regexp:first_match(Body, Regexp) of
{match, _, _} -> io:format("Language ~s exists @ ~s~n", [Language, URL]);
_ -> false
end;
{error, ErrorInfo} -> throw("Error: " ++ http:format_error(ErrorInfo))
end,
case http:request(URL) of
{ok, {_, _, Body}} ->
case regexp:first_match(Body, Regexp) of
{match, _, _} -> io:format("Language ~s exists @ ~s~n", [Language, URL]);
_ -> false
end;
{error, ErrorInfo} -> throw("Error: " ++ http:format_error(ErrorInfo))
end,
Send an email
Use library functions, classes or objects to create a short email addressed to your own email address. The subject should be,
"Greetings from langref.org", and the user should be prompted for the message body, and whether to cancel or proceed with sending the email.
perl
#SendSimpleEmail.pl
#
# Uses NET::SMTP to send an email to a specific email address
#Modification History
# 2009-MAR-17: GGARIEPY: [creation] (note: geoff.gariepy@gmail.com)
use strict;
use Net::SMTP; # See http://search.cpan.org/~gbarr/libnet-1.22/Net/SMTP.pm
my $smtpserver = 'some.smtp.server.fqdn.com'; # FQDN of SMTP server
my $fromaddress = 'somebody.surname@someemail.com';# Authorized user of SMTP server
my $subject = 'Greetings from langref.org'; # Subject of the message
my $recipient = 'geoff.gariepy@gmail.com'; # Recipient address
my @now;
# Prompt user for the message body to send
print "Enter the body of the message to send, then press Enter >";
my $message = <STDIN>; # String containing the body of the email
# Prompt user to see if execution should continue
print "Open connection to SMTP server [$smtpserver] to send your message? y/N [N] >";
my $yesorno = <STDIN>;
unless ($yesorno =~ /y/i ) {
print "Aborting send of message\n";
exit;
}
my $smtp = Net::SMTP->new($smtpserver, Debug => 1);# Connect to the SMTP server, and
# output diagnostics to STDOUT (DEBUG mode)
# Check to make sure connection was established; die if not.
if (!ref($smtp)) {
die("SENDMAIL: Couldn't establish session with $smtpserver! Message not sent!\n");
}
# Start the communication with the SMTP server by telling it we want
# to mail something.
$smtp->mail($fromaddress);
# Perl's NET::SMTP interface specifies the recipient(s) of the message by
# calls to the recipient method.
# Note that the method should be called once for each separate recipient
# (set up a loop to do this.)
# We're only going to do it once, however, since we only have one recipient.
$smtp->recipient($recipient);
# Figure out current date/time for the message date stamp
# Date stamp format is DD Monthname YY HH:MM:SS TIMEZONE
my @monthnames = qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec);
@now = gmtime(time);
for (0..$#now) {
# Make single-digit date/time elements two digits
if (length($now[$_]) lt 2) {$now[$_] = '0'.$now[$_];} # (i.e. prefix with '0')
}
# Slice off just the time and date elements we need from the output of gmtime()
my($YY, $MON, $DD, $HH, $MM, $SS) = @now[5,4,3,2,1,0];
$YY += 1900; # gmtime() epoch starts at 1900
my $monthname = $monthnames[$MON]; # Get the name of the month
# Finally build the silly date stamp!
my $datestring = "Date: $DD $monthname $YY $HH:$MM:$SS GMT";
# Tell the SMTP server we're about to send a block of message data
$smtp->data();
$smtp->datasend("$datestring"); # Give it the message date stamp
$smtp->datasend("From: $fromaddress\n"); # Send from address
$smtp->datasend("To: $recipient\n"); # Build the *display* list of 'to:' addresses
$smtp->datasend("Subject: $subject\n\n"); # Send subject delimited by two CRLFs
$smtp->datasend($message); # Send the message body
$smtp->dataend(); # Actually sends the message!!
$smtp->quit(); # Close the link to the SMTP server
__END__
#
# Uses NET::SMTP to send an email to a specific email address
#Modification History
# 2009-MAR-17: GGARIEPY: [creation] (note: geoff.gariepy@gmail.com)
use strict;
use Net::SMTP; # See http://search.cpan.org/~gbarr/libnet-1.22/Net/SMTP.pm
my $smtpserver = 'some.smtp.server.fqdn.com'; # FQDN of SMTP server
my $fromaddress = 'somebody.surname@someemail.com';# Authorized user of SMTP server
my $subject = 'Greetings from langref.org'; # Subject of the message
my $recipient = 'geoff.gariepy@gmail.com'; # Recipient address
my @now;
# Prompt user for the message body to send
print "Enter the body of the message to send, then press Enter >";
my $message = <STDIN>; # String containing the body of the email
# Prompt user to see if execution should continue
print "Open connection to SMTP server [$smtpserver] to send your message? y/N [N] >";
my $yesorno = <STDIN>;
unless ($yesorno =~ /y/i ) {
print "Aborting send of message\n";
exit;
}
my $smtp = Net::SMTP->new($smtpserver, Debug => 1);# Connect to the SMTP server, and
# output diagnostics to STDOUT (DEBUG mode)
# Check to make sure connection was established; die if not.
if (!ref($smtp)) {
die("SENDMAIL: Couldn't establish session with $smtpserver! Message not sent!\n");
}
# Start the communication with the SMTP server by telling it we want
# to mail something.
$smtp->mail($fromaddress);
# Perl's NET::SMTP interface specifies the recipient(s) of the message by
# calls to the recipient method.
# Note that the method should be called once for each separate recipient
# (set up a loop to do this.)
# We're only going to do it once, however, since we only have one recipient.
$smtp->recipient($recipient);
# Figure out current date/time for the message date stamp
# Date stamp format is DD Monthname YY HH:MM:SS TIMEZONE
my @monthnames = qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec);
@now = gmtime(time);
for (0..$#now) {
# Make single-digit date/time elements two digits
if (length($now[$_]) lt 2) {$now[$_] = '0'.$now[$_];} # (i.e. prefix with '0')
}
# Slice off just the time and date elements we need from the output of gmtime()
my($YY, $MON, $DD, $HH, $MM, $SS) = @now[5,4,3,2,1,0];
$YY += 1900; # gmtime() epoch starts at 1900
my $monthname = $monthnames[$MON]; # Get the name of the month
# Finally build the silly date stamp!
my $datestring = "Date: $DD $monthname $YY $HH:$MM:$SS GMT";
# Tell the SMTP server we're about to send a block of message data
$smtp->data();
$smtp->datasend("$datestring"); # Give it the message date stamp
$smtp->datasend("From: $fromaddress\n"); # Send from address
$smtp->datasend("To: $recipient\n"); # Build the *display* list of 'to:' addresses
$smtp->datasend("Subject: $subject\n\n"); # Send subject delimited by two CRLFs
$smtp->datasend($message); # Send the message body
$smtp->dataend(); # Actually sends the message!!
$smtp->quit(); # Close the link to the SMTP server
__END__
Process an XML document
Given the XML Document:
<shopping>
<item name=
<item name=
</shopping>
Print out the total cost of the items, e.g. $14.50
<shopping>
<item name=
"bread" quantity="3" price="2.50"/>
<item name=
"milk" quantity="2" price="3.50"/>
</shopping>
Print out the total cost of the items, e.g. $14.50
perl
#! /usr/bin/perl
# -*- Mode: CPerl -*-
use strict;
use XML::Simple;
use Data::Dumper;
# Given the XML Document:
#
# <shopping>
# <item name="bread" quantity="3" price="2.50"/>
# <item name="milk" quantity="2" price="3.50"/>
# </shopping>
#
# Print out the total cost of the items, e.g. $14.50
my $xml =
" <shopping>\n"
." <item name=\"bread\" quantity=\"3\" price=\"2.50\"/>\n"
." <item name=\"milk\" quantity=\"2\" price=\"3.50\"/>\n"
." </shopping>\n";
my $xs = XML::Simple->new();
my $ref = $xs->XMLin($xml);
my $stuff = ${$ref}{item};
my $q;
my $p;
my $t;
my $z;
foreach my $item ( sort keys %{$stuff}){
$q = ${$stuff}{$item}{quantity};
$p = ${$stuff}{$item}{price};
$z = $q*$p;
printf "%5.5s %2d @\$%5.2f = \$%5.2f\n",$item,$q,$p,$z;
$t += $z;
}
printf "Total \$%5.2f\n",$t;
#eos
# -*- Mode: CPerl -*-
use strict;
use XML::Simple;
use Data::Dumper;
# Given the XML Document:
#
# <shopping>
# <item name="bread" quantity="3" price="2.50"/>
# <item name="milk" quantity="2" price="3.50"/>
# </shopping>
#
# Print out the total cost of the items, e.g. $14.50
my $xml =
" <shopping>\n"
." <item name=\"bread\" quantity=\"3\" price=\"2.50\"/>\n"
." <item name=\"milk\" quantity=\"2\" price=\"3.50\"/>\n"
." </shopping>\n";
my $xs = XML::Simple->new();
my $ref = $xs->XMLin($xml);
my $stuff = ${$ref}{item};
my $q;
my $p;
my $t;
my $z;
foreach my $item ( sort keys %{$stuff}){
$q = ${$stuff}{$item}{quantity};
$p = ${$stuff}{$item}{price};
$z = $q*$p;
printf "%5.5s %2d @\$%5.2f = \$%5.2f\n",$item,$q,$p,$z;
$t += $z;
}
printf "Total \$%5.2f\n",$t;
#eos
use strict;
use XML::Twig;
use Data::Dumper;
my $xml = <<ENDXML;
<shopping>
<item name="bread" quantity="3" price="2.50"/>
<item name="milk" quantity="2" price="3.50"/>
</shopping>
ENDXML
my $xt = XML::Twig->parse( $xml );
my $price;
foreach my $item ($xt->root->children('item')) {
$price += ($item->{att}{price} * $item->{att}{quantity})
}
printf "Total Cost: %.2f\n", $price
use XML::Twig;
use Data::Dumper;
my $xml = <<ENDXML;
<shopping>
<item name="bread" quantity="3" price="2.50"/>
<item name="milk" quantity="2" price="3.50"/>
</shopping>
ENDXML
my $xt = XML::Twig->parse( $xml );
my $price;
foreach my $item ($xt->root->children('item')) {
$price += ($item->{att}{price} * $item->{att}{quantity})
}
printf "Total Cost: %.2f\n", $price
erlang
-include_lib("xmerl/include/xmerl.hrl").
-export([get_total/1]).
get_total(ShoppingList) ->
{XmlElt, _} = xmerl_scan:string(ShoppingList),
Items = xmerl_xpath:string("/shopping/item", XmlElt),
Total = lists:foldl(fun(Item, Tot) ->
[#xmlAttribute{value = PriceString}] = xmerl_xpath:string("/item/@price", Item),
{Price, _} = string:to_float(PriceString),
[#xmlAttribute{value = QuantityString}] = xmerl_xpath:string("/item/@quantity", Item),
{Quantity, _} = string:to_integer(QuantityString),
Tot + Price*Quantity
end,
0, Items),
io:format("$~.2f~n", [Total]).
-export([get_total/1]).
get_total(ShoppingList) ->
{XmlElt, _} = xmerl_scan:string(ShoppingList),
Items = xmerl_xpath:string("/shopping/item", XmlElt),
Total = lists:foldl(fun(Item, Tot) ->
[#xmlAttribute{value = PriceString}] = xmerl_xpath:string("/item/@price", Item),
{Price, _} = string:to_float(PriceString),
[#xmlAttribute{value = QuantityString}] = xmerl_xpath:string("/item/@quantity", Item),
{Quantity, _} = string:to_integer(QuantityString),
Tot + Price*Quantity
end,
0, Items),
io:format("$~.2f~n", [Total]).
csharp
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.LoadXml(
@"<shopping>
<item name='bread' quantity='3' price='2.50'/>
<item name='milk' quantity='2' price='3.50'/>
</shopping>");
string decimalSeparator= System.Globalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator;
double sum=0;
foreach(System.Xml.XmlNode nodo in doc.SelectNodes("/shopping/item")){
sum += int.Parse(nodo.Attributes["quantity"].InnerText) * double.Parse(nodo.Attributes["price"].InnerText.Replace(".",decimalSeparator));
}
Console.WriteLine("{0:#.00}",sum);
doc.LoadXml(
@"<shopping>
<item name='bread' quantity='3' price='2.50'/>
<item name='milk' quantity='2' price='3.50'/>
</shopping>");
string decimalSeparator= System.Globalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator;
double sum=0;
foreach(System.Xml.XmlNode nodo in doc.SelectNodes("/shopping/item")){
sum += int.Parse(nodo.Attributes["quantity"].InnerText) * double.Parse(nodo.Attributes["price"].InnerText.Replace(".",decimalSeparator));
}
Console.WriteLine("{0:#.00}",sum);
create some XML programmatically
Given the following CSV:
bread,3,2.50
milk,2,3.50
Produce the equivalent information in XML, e.g.:
<shopping>
<item name=
<item name=
</shopping>
bread,3,2.50
milk,2,3.50
Produce the equivalent information in XML, e.g.:
<shopping>
<item name=
"bread" quantity="3" price="2.50" />
<item name=
"milk" quantity="2" price="3.50" />
</shopping>
perl
#! /usr/bin/perl
# -*- Mode: CPerl -*-
use strict;
use XML::Simple;
use Data::Dumper;
# bread,3,2.50
# milk,2,3.50
#
# Produce the equivalent information in XML, e.g.:
#
# <shopping>
# <item name="bread" quantity="3" price="2.50" />
# <item name="milk" quantity="2" price="3.50" />
# </shopping>
#
my $line;
my $item;
my $q;
my $p;
my $z;
my $xs = XML::Simple->new();
my %d = ();
while($line=<DATA>){
chomp $line;
($item,$q,$p) = split ",",$line;
$d{shopping}{item}{$item}{quantity} = $q;
$d{shopping}{item}{$item}{price} = $p;
}
$xml = $xs->XMLout(\%d, KeepRoot => 1);
print $xml,"\n";
__DATA__
bread,3,2.50
milk,2,3.50
# -*- Mode: CPerl -*-
use strict;
use XML::Simple;
use Data::Dumper;
# bread,3,2.50
# milk,2,3.50
#
# Produce the equivalent information in XML, e.g.:
#
# <shopping>
# <item name="bread" quantity="3" price="2.50" />
# <item name="milk" quantity="2" price="3.50" />
# </shopping>
#
my $line;
my $item;
my $q;
my $p;
my $z;
my $xs = XML::Simple->new();
my %d = ();
while($line=<DATA>){
chomp $line;
($item,$q,$p) = split ",",$line;
$d{shopping}{item}{$item}{quantity} = $q;
$d{shopping}{item}{$item}{price} = $p;
}
$xml = $xs->XMLout(\%d, KeepRoot => 1);
print $xml,"\n";
__DATA__
bread,3,2.50
milk,2,3.50
use strict;
use XML::Writer;
use Text::CSV;
my $csv = <<ENDOFCSV;
bread,3,2.50
milk,2,3.50
ENDOFCSV
open my $fh, '<', \$csv or die "Can't open string, $!\n";
my $csv = Text::CSV->new;
my $writer = XML::Writer->new(DATA_MODE => 1, DATA_INDENT => 2);
$writer->startTag('shopping');
while (my $arr_ref = $csv->getline($fh)) {
my %attributes;
@attributes{qw/name quantity price/} =
@{$arr_ref}[0..2];
$writer->emptyTag('item' => %attributes)
}
$writer->endTag('shopping');
use XML::Writer;
use Text::CSV;
my $csv = <<ENDOFCSV;
bread,3,2.50
milk,2,3.50
ENDOFCSV
open my $fh, '<', \$csv or die "Can't open string, $!\n";
my $csv = Text::CSV->new;
my $writer = XML::Writer->new(DATA_MODE => 1, DATA_INDENT => 2);
$writer->startTag('shopping');
while (my $arr_ref = $csv->getline($fh)) {
my %attributes;
@attributes{qw/name quantity price/} =
@{$arr_ref}[0..2];
$writer->emptyTag('item' => %attributes)
}
$writer->endTag('shopping');
erlang
to_xml(ShoppingList) ->
Items = lists:map(fun(L) ->
[Name, Quantity, Price] = string:tokens(L, ","),
{item, [{name, Name}, {quantity, Quantity}, {price, Price}], []}
end, string:tokens(ShoppingList, "\n")),
xmerl:export_simple([{shopping, [], Items}], xmerl_xml).
Items = lists:map(fun(L) ->
[Name, Quantity, Price] = string:tokens(L, ","),
{item, [{name, Name}, {quantity, Quantity}, {price, Price}], []}
end, string:tokens(ShoppingList, "\n")),
xmerl:export_simple([{shopping, [], Items}], xmerl_xml).
csharp
string cvs ="bread,3,2.50\nmilk,2,3.50";
IList<string> rows = cvs.Split('\n');
System.Text.StringBuilder sb = new System.Text.StringBuilder("<shopping>");
foreach(string row in rows){
IList<string> data = row.Split(',');
sb.AppendFormat("<item name='{0}' quantity='{1}' price='{2}' />",data[0],data[1],data[2]);
}
sb.Append("</shopping>");
IList<string> rows = cvs.Split('\n');
System.Text.StringBuilder sb = new System.Text.StringBuilder("<shopping>");
foreach(string row in rows){
IList<string> data = row.Split(',');
sb.AppendFormat("<item name='{0}' quantity='{1}' price='{2}' />",data[0],data[1],data[2]);
}
sb.Append("</shopping>");
Find all Pythagorean triangles with length or height less than or equal to 20
Pythagorean triangles are right angle triangles whose sides comply with the following equation:
a * a + b * b = c * c
where c represents the length of the hypotenuse, and a and b represent the lengths of the other two sides. Find all such triangles where a, b and c are non-zero integers with a and b less than or equal to 20. Sort your results by the size of the hypotenuse. The expected answer is:
a * a + b * b = c * c
where c represents the length of the hypotenuse, and a and b represent the lengths of the other two sides. Find all such triangles where a, b and c are non-zero integers with a and b less than or equal to 20. Sort your results by the size of the hypotenuse. The expected answer is:
[3, 4, 5]
[6, 8, 10]
[5, 12, 13]
[9, 12, 15]
[8, 15, 17]
[12, 16, 20]
[15, 20, 25]
perl
#!/usr/bin/perl
my @results;
for my $x (1..20) {
for my $y ($x..20) {
my $z = sqrt($x**2+$y**2);
push @results, [$x,$y,$z] if $z == int($z);
}
}
for my $triangle ( sort { $a->[2] <=> $b->[2] } @results) {
print "[".join(',',@$triangle)."]\n";
}
my @results;
for my $x (1..20) {
for my $y ($x..20) {
my $z = sqrt($x**2+$y**2);
push @results, [$x,$y,$z] if $z == int($z);
}
}
for my $triangle ( sort { $a->[2] <=> $b->[2] } @results) {
print "[".join(',',@$triangle)."]\n";
}
erlang
find_all_pythagorean_triangles(L) ->
lists:sort(fun({_, _, H1}, {_, _, H2}) -> H1 =< H2 end,
[ { X, Y, Z } ||
X <- lists:seq(1,L),
Y <- lists:seq(1,L),
Z <- lists:seq(1,2*L),
X*X + Y*Y =:= Z*Z,
Y > X,
Z > Y
]).
main(_) ->
List = find_all_pythagorean_triangles(20).
lists:sort(fun({_, _, H1}, {_, _, H2}) -> H1 =< H2 end,
[ { X, Y, Z } ||
X <- lists:seq(1,L),
Y <- lists:seq(1,L),
Z <- lists:seq(1,2*L),
X*X + Y*Y =:= Z*Z,
Y > X,
Z > Y
]).
main(_) ->
List = find_all_pythagorean_triangles(20).
Greatest Common Divisor
Find the largest positive integer that divides two given numbers without a remainder. For example, the GCD of 8 and 12 is 4.
perl
sub gcd {
my ($a, $b) = @_;
($a,$b) = ($b,$a) if $a > $b;
while ($a) { ($a, $b) = ($b % $a, $a) }
return $b;
}
print gcd( 8, 12 );
my ($a, $b) = @_;
($a,$b) = ($b,$a) if $a > $b;
while ($a) { ($a, $b) = ($b % $a, $a) }
return $b;
}
print gcd( 8, 12 );
my $g = gcd (8, 12);
print $g;
sub gcd {
# Euclid's Algorithm - recursive
my ($c, $d) = @_;
return $c unless $d;
return gcd ($d, $c % $d);
}
print $g;
sub gcd {
# Euclid's Algorithm - recursive
my ($c, $d) = @_;
return $c unless $d;
return gcd ($d, $c % $d);
}
my $g = gcd2 (8, 12);
print $g;
sub gcd2 {
# Dijkstra's Algorithm - recursive
my ($c, $d) = @_;
return $c if $c == $d;
return $c > $d? gcd2 ($c - $d, $d) : gcd2 ($c, $d - $c);
}
print $g;
sub gcd2 {
# Dijkstra's Algorithm - recursive
my ($c, $d) = @_;
return $c if $c == $d;
return $c > $d? gcd2 ($c - $d, $d) : gcd2 ($c, $d - $c);
}
erlang
-module(gcd).
-export([gcd/2]).
gcd(A, 0) -> A;
gcd(A, B) -> gcd(B, A rem B).
-export([gcd/2]).
gcd(A, 0) -> A;
gcd(A, B) -> gcd(B, A rem B).
csharp
public static int gcd(int a, int b)
{
if (b == 0)
return a;
else
return gcd(b, a % b);
}
{
if (b == 0)
return a;
else
return gcd(b, a % b);
}
produces a copy of its own source code
In computing, a quine is a computer program which produces a copy of its own source code as its only output.
perl
seek DATA,0,0;
print <DATA>;
__DATA__
Cheating quine.
print <DATA>;
__DATA__
Cheating quine.
$_=q(print qq(\$_=q($_);eval\n));eval
$x=q($x=q(%s);printf($x,$x););printf($x,$x);
Subdivide A Problem To A Pool Of Workers (No Shared Data)
Take a hard to compute problem and split it up between multiple worker threads. In your solution, try to fully utilize available cores or processors. (I'm looking at you, Python!)
Note: In this question, there should be no need for shared state between worker threads while the problem is being solved. Only after every thread completes computation are the answers recombined into a single output.
Example:
-Input-
(In python syntax)
In other words, a list of random strings.
-Output-
(In python syntax)
In other words, all possible permutations of each input string are computed.
Note: In this question, there should be no need for shared state between worker threads while the problem is being solved. Only after every thread completes computation are the answers recombined into a single output.
Example:
-Input-
(In python syntax)
["ab", "we", "tfe", "aoj"]
In other words, a list of random strings.
-Output-
(In python syntax)
[ ["ab", "ba", "aa", "bb", "a", "b"], ["we", "ew", "ww", "ee", "w", "e"], ...
In other words, all possible permutations of each input string are computed.
Subdivide A Problem To A Pool Of Workers (Shared Data)
Take a hard to compute problem and split it up between multiple worker threads. In your solution, try to fully utilize available cores or processors. (I'm looking at you, Python!)
Note: In this question, there should be a need for shared state between worker threads while the problem is being solved.
Example:
-Conway Game of Life-
From Wikipedia:
The universe of the Game of Life is an infinite two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, live or dead. Every cell interacts with its eight neighbors, which are the cells that are directly horizontally, vertically, or diagonally adjacent. At each step in time, the following transitions occur:
1. Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
2. Any live cell with more than three live neighbours dies, as if by overcrowding.
3. Any live cell with two or three live neighbours lives on to the next generation.
4. Any dead cell with exactly three live neighbours becomes a live cell.
The initial pattern constitutes the seed of the system. The first generation is created by applying the above rules simultaneously to every cell in the seed—births and deaths happen simultaneously, and the discrete moment at which this happens is sometimes called a tick (in other words, each generation is a pure function of the one before). The rules continue to be applied repeatedly to create further generations.
--However, for our purposes, we will assign a size to the game
Notice that in this problem, at each step or
Note: In this question, there should be a need for shared state between worker threads while the problem is being solved.
Example:
-Conway Game of Life-
From Wikipedia:
The universe of the Game of Life is an infinite two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, live or dead. Every cell interacts with its eight neighbors, which are the cells that are directly horizontally, vertically, or diagonally adjacent. At each step in time, the following transitions occur:
1. Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
2. Any live cell with more than three live neighbours dies, as if by overcrowding.
3. Any live cell with two or three live neighbours lives on to the next generation.
4. Any dead cell with exactly three live neighbours becomes a live cell.
The initial pattern constitutes the seed of the system. The first generation is created by applying the above rules simultaneously to every cell in the seed—births and deaths happen simultaneously, and the discrete moment at which this happens is sometimes called a tick (in other words, each generation is a pure function of the one before). The rules continue to be applied repeatedly to create further generations.
--However, for our purposes, we will assign a size to the game
"board": 2^k * 2^k . That is, the board should be easy to subdivide.
Notice that in this problem, at each step or
"tick", each thread/process will need to share data with its neighborhood.
Create a multithreaded "Hello World"
Create a program which outputs the string
Example:
-Output-
Thread one says Hello World!
Thread two says Hello World!
Thread four says Hello World!
Thread three says Hello World!
-Notice that the threads can print in any order.
"Hello World" to the console, multiple times, using separate threads or processes.
Example:
-Output-
Thread one says Hello World!
Thread two says Hello World!
Thread four says Hello World!
Thread three says Hello World!
-Notice that the threads can print in any order.
perl
use threads;
foreach my $tid ("one","two","three","four") {
threads->create(
sub { print("Thread $tid says Hello World!\n"); }
)->join();
}
foreach my $tid ("one","two","three","four") {
threads->create(
sub { print("Thread $tid says Hello World!\n"); }
)->join();
}
erlang
-module(spam).
-export([spam/1]).
spam(N) when N<5 ->
spawn(fun() -> io:format("Hello World from thread ~p~n",[N]) end),
spam(N+1);
spam(_) -> void.
-export([spam/1]).
spam(N) when N<5 ->
spawn(fun() -> io:format("Hello World from thread ~p~n",[N]) end),
spam(N+1);
spam(_) -> void.
Create read/write lock on a shared resource.
Create multiple threads or processes who are either readers or writers. There should be more readers then writers.
(From Wikipedia):
Multiple readers can read the data in parallel but an exclusive lock is needed while writing the data. When a writer is writing the data, readers will be blocked until the writer is finished writing.
Example:
-Output-
Thread one says that the value is 8.
Thread three says that the value is 8.
Thread two is taking the lock.
Thread four tried to read the value, but could not.
Thread five tried to write to the value, but could not.
Thread two is changing the value to 9.
Thread two is releasing the lock.
Thread four says that the value is 9.
...
--Notice that when a needed resource is locked, a thread can set a timer and try again in the future, or wait to be notified that the resource is no longer locked.
(From Wikipedia):
Multiple readers can read the data in parallel but an exclusive lock is needed while writing the data. When a writer is writing the data, readers will be blocked until the writer is finished writing.
Example:
-Output-
Thread one says that the value is 8.
Thread three says that the value is 8.
Thread two is taking the lock.
Thread four tried to read the value, but could not.
Thread five tried to write to the value, but could not.
Thread two is changing the value to 9.
Thread two is releasing the lock.
Thread four says that the value is 9.
...
--Notice that when a needed resource is locked, a thread can set a timer and try again in the future, or wait to be notified that the resource is no longer locked.
Separate user interaction and computation.
Allow your program to accept user interaction while conducting a long running computation.
Example:
Hello user! Please input a string to permute: (input thread)
abcdef
Passing on abcdef... (input thread)
Please input another string to permute: (input thread)
lol
Passing on lol... (input thread)
Done Work On abcdef! (worker thread)
Please input another string to permute: (input thread)
EXIT
Quitting, I
--Notice, that this could be accomplished on the command line or within a GUI. The point is that computation and user interaction should take place on separate threads of control.
Example:
Hello user! Please input a string to permute: (input thread)
abcdef
Passing on abcdef... (input thread)
Please input another string to permute: (input thread)
lol
Passing on lol... (input thread)
Done Work On abcdef! (worker thread)
["abcdef", "abcefd", ... ] (worker thread)
Please input another string to permute: (input thread)
EXIT
Quitting, I
'll let my worker thread know... (input thread)
We're quitting! Alright! (worker thread)
--Notice, that this could be accomplished on the command line or within a GUI. The point is that computation and user interaction should take place on separate threads of control.
Put a internationalizate of HelloWorld program
Set locale to
In pseudocode:
Void main ()
"es" (spanish) and provide a program that changes outputs ("Helloworld") depending of locale.
In pseudocode:
Void main ()
{
Locale.set("es")
print.translate("Helloworld, Locale.get)
}
180
"http://www.ecigarettefresh.com/cartomizer-ecigarette-c-7.html ">Cartomizer E-Cigarette<
/a>strong>"http://www.ecigarettefresh.com/cartomizer-ecigarette-c-7.html ">Electronic Cigarette<
/a>strong>"http://www.ecigarettefresh.com/cartomizer-ecigarette-c-7.html ">Smokeless Cigarettes<
/a>strong>"http://www.ecigarettefresh.com/cartomizer-ecigarette-c-7.html ">discount Electronic Cigarette<
/a>strong>"http://www.ecigarettefresh.com/disposable-ecigarette-c-8.html ">Disposable E-Cigarette<
/a>strong>"http://www.ecigarettefresh.com/accessories-c-6.html ">Accessories<
/a>strong>"http://www.ecigarettefresh.com/mini-ecigarette-c-13.html ">Mini E-cigarette<
/a>strong>"http://www.ecigarettefresh.com/esmoking-c-11.html ">electric cigarette outlet<
/a>strong>"http://www.ecigarettefresh.com/smokeless-cigarettes-c-12.html ">Smokeless Cigarettes online<
/a>strong>"http://www.ecigarettefresh.com/ecigarette-c-9.html ">Electronic Cigarette online<
/a>strong>. "http://blog.allluxurywatches.com"> outlet blog <
/a>
outlet a>"http://blog.linksoflondonshopping.com"> About ecigarettefresh.com blog
180
"http://www.lovembtshoes.com/ ">mbt boots<
/a>strong>"http://www.lovembtshoes.com/ ">mbt shoes<
/a>strong>"http://www.lovembtshoes.com/ ">buy mbt boots<
/a>strong>"http://www.lovembtshoes.com/ ">discount mbt shoes<
/a>strong>"http://www.lovembtshoes.com/ ">mbt shoes online<
/a>strong>"http://www.lovembtshoes.com/mbt-tariki-c-50.html ">MBT Tariki shoes outlet<
/a>strong>"http://www.lovembtshoes.com/mbt-karibu-c-18.html ">wholesale MBT Karibu shoes<
/a>strong>"http://www.lovembtshoes.com/mbt-kafala-black-leather-women-shoes-p-68.html ">buy MBT Kafala shoes<
/a>strong>"http://www.lovembtshoes.com/mbt-meli-c-33.html ">MBT Meli<
/a>strong>"http://www.lovembtshoes.com/mbt-kifundo-c-25.html ">discount MBT Kifundo<
/a>strong>. "http://blog.bootsonlinecompany.com"> Bia blog <
/a>
Bia a>"http://blog.linkuggbootsoutlet.com"> About lovembtshoes.com blog
180
[Mall3411] - $175.01 : </title>
html; charset=utf-8" />
keywords" content="Low Cost Custom-Made bretelles sexy mariage mariée robe de mariée Robes [Mall3411] Robes de Mariée Robes de mariée 2012 Robe de mariée sexy Robes de mariée robes Quinceanera Robes de bal Robes de soirée Robes de bal Robes de soirée Robes de cocktail " />
description" content=" Low Cost Custom-Made bretelles sexy mariage mariée robe de mariée Robes [Mall3411] - Nom de l'article: " />
- TOP_MENU_HOME
- Robes de cocktail
- Robes de soirée
- Robes de mariée
- Robes de bal
- Contactez-nous
- http:
//fr.weddingdressescompany.com/»,«http:/fr.weddingdressescompany.com/' ) " > Marque page