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Strings

Printing

Output a string to the console

Write the string "Hello World!" to STDOUT

ruby

puts "Hello World!"

$stdout<<"Hello World!"

erlang

io:format("Hello, World!~n").

csharp

System.Console.WriteLine("Hello World!")

fsharp

printfn "Hello World!"

groovy

println "Hello World!"

java

System.out.println("Hello World!");

System.out.printf("Hello World!\n");

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 "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?

ruby

gem 'uri-query_params'
require 'uri/query_params'

url = URI("http://myserver.com/custinfo/edit.php?mode=view&fname=Ron%20&%20Jean&lname=Smith")
url.query_params['fname']
# => "Ron & Jean"

url = "http://myserver.com/custinfo/edit.php?mode=view&fname=Ron & Jean&lname=Smith"
url = URI.parse(URI.encode(url))

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, "&"),...

fsharp

//the problem arises due to the fact that you've attempted to apply HTML entities encoding rather than URL encoding to your data!
//in F#, for example, assuming you would call this function with fname and lname parameters, this would produce the desired output
let getProperUrl fname lname = sprintf "http://myserver.com/custinfo/edit.php?mode=view&fname=%s&lname=%s" (HttpUtility.UrlEncode fname) (HttpUtility.UrlEncode lname)

// Example that shows encoding and decoding:
let queryString =
let fname = HttpUtility.UrlEncode("Ron & James")
let lname = HttpUtility.UrlEncode("Smith & Jones")
sprintf "http://myserver.com/custinfo/edit.php?mode=view&fname=%s&lname=%s" fname lname
/// All parameters in the URL as a lookup map
let parameters =
let paramStart = queryString.IndexOf('?')
if paramStart < 0 then
Map.empty
else
let values =
queryString.Substring(paramStart + 1)
|> HttpUtility.ParseQueryString
values.AllKeys
|> Seq.map (fun key -> key, values.[key])
|> Map.ofSeq
let fname = parameters.TryFind("fname")
let lname = parameters.TryFind("lname")

groovy

// Given the nature of the question text, I am assuming the question
// is how to produce a application/x-www-form-urlencoded compliant string

def basename = 'http://somedomain.com/somebase/'
def parameter = 'Bart & Lisa'
// equivalent to php
println basename + URLEncoder.encode(parameter)
// recommended approach is to specify encoding
println basename + URLEncoder.encode(parameter, "UTF-8")

java

Map<String, String> params = new HashMap<String, String>();
params.put("mode", "view");
params.put("fname", "Ron & Jean");
params.put("lname", "Smith");

StringBuilder buffer = new StringBuilder();
for (Map.Entry<String, String> entry : params.entrySet()) {
buffer.append(URLEncoder.encode(entry.getKey(), "UTF-8"))
.append("=")
.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
}
System.out.println(buffer.toString());

string-wrap

Wrap the string "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.

ruby

str = "The quick brown fox jumps over the lazy dog. " * 10
outarr = str.scan(/[^ ].{0,76}/)
outarr.each{ |line| puts "> %s" % line }

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]).

groovy

'The quick brown fox jumps over the lazy dog. '.multiply(10).split('(?<=\\G.{76})').each{println '> ' + it}

st = "The quick brown fox jumps over the lazy dog. " * 10
width = 76
while(st){
(first, st) = st.length() > width? [st[0..width], st[(width+1)..-1].trim()] : [st, null]
println "> $first"
}

java

public class SolutionXX {
public static void main(String[] args) {
StringBuilder builder = new StringBuilder();
String words = "The quick brown fox jumps over the lazy dog. ";

for (int i = 0; i < 10; i++)
{
builder.append(words);
}

String toWrap = builder.toString();
int width = 76;
while (toWrap!=null && toWrap.length()>0)
{
String first = toWrap.length() > width ? toWrap.substring(0, width+1) : toWrap;
toWrap = (!toWrap.equals(first)) ? toWrap.substring(width + 1).trim() : null;
System.out.println("> " + first);
}

}
}

Declaration

Define a string containing special characters

Define the literal string "\#{'}${"}/"

ruby

special = '\#{\'}${"}/'

erlang

Special = "\\#{'}\${\"}/",

csharp

string verbatim = @"\#{'}${""""}/";
string cStyle = "\\#{'}${\"\"}/";

fsharp

let special = "\#{'}${\"}/"

groovy

special = "\\#{'}\${\"}/"

special = '\\#{\'}${"}/'

special = /\#{'}${'$'}{"}\//

java

String special = "\\#{'}${\"}/";

Define a multiline string

Define the string:

"This

Is

A

Multiline

String"

ruby

text = <<"HERE"
This
Is
A
Multiline
String
HERE

text = "This\nIs\nA\nMultiline\nString"

erlang

Text = "This\nIs\nA\nMultiline\nString",

csharp

string output = "This\nIs\nA\nMultiline\nString";

string output = @"This
Is
A
Multiline
String";

fsharp

let multiline = "This\nIs\nA\nMultiline\nString"

let multiline = "This
Is
A
Multiline
String"

groovy

def text =
"""This
Is
A
Multiline
String"""

def text = "This\nIs\nA\nMultiline\nString"

java

String text = "This\nIs\nA\nMultiline\nString";

String text =
"This\n" +
"Is\n" +
"A\n" +
"Multiline\n" +
"String"

Define a string containing variables and expressions

Given variables a=3 and b=4 output "3+4=7"

ruby

puts "#{a}+#{b}=#{a+b}"

puts "#{a}+#{b}=%s" % (a + b)

erlang

A = 3, B = 4,
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);

fsharp

let a, b = 3, 4
let mystr = sprintf "%d+%d=%d" a b (a+b)
printfn "%s" mystr

groovy

println "$a+$b=${a+b}"

printf "%d+%d=%d\n", a, b, a + b

java

System.out.println(a + "+" + b + "=" + (a+b));

System.out.printf("%d+%d=%d\n", a, b, a + b);

Manipulation

Reverse the characters in a string

Given the string "reverse me", produce the string "em esrever"

ruby

puts "reverse me".reverse

erlang

Reversed = lists:reverse("reverse me"),

Reversed = revchars("reverse me"),

csharp

var str = "reverse me";
Console.WriteLine(new String(str.Reverse().ToArray()));

fsharp

let reversed = new String (Array.rev ("reverse me".ToCharArray()))

let word = "reverse me"
//reverse the word
let reversedword =
word.ToCharArray()
|> Array.fold(fun acc x -> x::acc) []

groovy

reversed = "reverse me".reverse()

java

String reverse = new StringBuffer("reverse me").reverse().toString();

String reverse = new StringBuilder("reverse me").reverse().toString();

String reverse = StringUtils.reverse("reverse me");

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"

ruby

reversed = text.split.reverse.join(' ')

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);

fsharp

let reversed = String.Join(" ", Array.rev("This is the end, my only friend!".Split [|' '|]))

groovy

reversed = "This is the end, my only friend!".split().reverse().join(' ')

reversed = "This is the end, my only friend!".tokenize(' ').reverse().join(' ')

def revdelim(c, s) { StringUtils.reverseDelimited(s, c) }
revwords = this.&revdelim.curry(" " as char)
reversed = revwords("This is the end, my only friend!")

reversed = StringUtils.reverseDelimited("This is the end, my only friend!", " " as char)

java

List list = new ArrayList();
StringTokenizer st = new StringTokenizer(text, " ");
while(st.hasMoreTokens()) {
list.add(0, st.nextToken());
}
StringBuffer sb = new StringBuffer();
for (Iterator iterator = list.iterator(); iterator.hasNext();) {
String word = (String) iterator.next();
sb.append(word);
if (iterator.hasNext()) {
sb.append(" ");
}
}
String reversed = sb.toString();

List<String> ls = Arrays.asList("This is the end, my only friend!".split("\\s"));
Collections.reverse(ls);
StringBuilder sb = new StringBuilder(32); for (String s : ls) sb.append(" ").append(s);
String reversed = sb.toString().trim();

String reversed = StringUtils.reverseDelimited("This is the end, my only friend!", ' ');

Text wrapping

Wrap the string "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.

ruby

prefix = "> "
string = "The quick brown fox jumps over the lazy dog. " * 10
width = 78
realwidth = width - prefix.length
print string.gsub(/(.{1,#{realwidth}})(?: +|$)\n?|(.{#{realwidth}})/, "#{prefix}\\1\\2\n")

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")).

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));
}
}

fsharp

let prefix = "> "
let input = "The quick brown fox jumps over the lazy dog. "

(String.split ['\n'] (textwrap (copies input 10) (73 - prefix.Length))) |> List.iter (fun line -> printfn "%s%s" prefix line)

let output maxWidth (s: string) =
let rec wrap = function
| lineSoFar, ([| |]: string array)-> printfn "%s" lineSoFar
| ">" as lineSoFar, (words: string array) ->
// Handle this case separately, thus we can also deal with
// cases where a word is longer then the max width
wrap (lineSoFar + " " + words.[0], Array.sub words 1 (words.Length - 1))
| lineSoFar, words when words.[0].Length + lineSoFar.Length >= maxWidth ->
printfn "%s" lineSoFar
wrap (">", words)
| lineSoFar, words ->
wrap(lineSoFar + " " + words.[0], Array.sub words 1 (words.Length - 1))
wrap (">", s.Split([| ' ' |]))

[| for i in 1 .. 10 do yield "The quick brown fox jumps over the lazy dog." |]
|> String.concat " "
|> output 78

groovy

// no built-in fill, define one using brute force approach
def fill(text, width=80, prefix='') {
width = width - prefix.size()
def out = []
List words = text.replaceAll("\n", " ").split(" ")
while (words) {
def line = ''
while (words) {
if (line.size() + words[0].size() + 1 > width) break
if (line) line += ' '
line += words[0]
words = words.tail()
}
out += prefix + line
}
out.join("\n")
}
println fill('The quick brown fox jumps over the lazy dog. ' * 10, 72, '> ')

// no built-in fill, define one using lastIndexOf
def fill(text, width=80, prefix='') {
def out = ''
def remaining = text.replaceAll("\n", " ")
while (remaining) {
def next = prefix + remaining
def found = next.lastIndexOf(' ', width)
if (found == -1) remaining = ''
else {
remaining = next.substring(found + 1)
next = next[0..found]
}
out += next + '\n'
}
out
}
println fill('The quick brown fox jumps over the lazy dog. ' * 10, 72, '> ')

prefix = '> '
input = 'The quick brown fox jumps over the lazy dog. '
wrap(input * 10, 72 - prefix.size()).eachLine{ println prefix + it }

java

String prefix = "> "; String input = "The quick brown fox jumps over the lazy dog.";

String[] lines = WordUtils.wrap(StringUtils.repeat(input, 10), 72 - prefix.length()).split("\n");

for (String line : lines) System.out.printf("%s%s\n", prefix, line);

Remove leading and trailing whitespace from a string

Given the string " hello " return the string "hello".

ruby

puts " hello ".strip

" hello ".strip!

erlang

Trimmed = string:strip(S),

csharp

string str = " hello ";
str = str.Trim();
Console.WriteLine(str);

fsharp

let s = " hello "
let trimmed = s.Trim()

let trimmed = " hello ".Trim()

groovy

assert "hello" == " hello ".trim()

java

String s = " hello "; String trimmed = s.trim();

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

ruby

rot13 = "Hello World #123".tr!("A-Za-z", "N-ZA-Mn-za-m")
rot47 = "Hello World #123".tr!("\x21-\x7e", "\x50-\x7e\x21-\x4f")

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).

fsharp

#light

let rotChar (s:int) (l:int) (h:int) (c:char) =
let charCode = int c
let letterCount = h - l + 1
let newCharCode = (charCode - l + s) % letterCount + l
char newCharCode

let rot13 (text:string) =
let rotChar13 = function
| (c:char) when 'A' <= c && c <= 'Z' -> rotChar 13 (int 'A') (int 'Z') c
| c when 'a' <= c && c <= 'z' -> rotChar 13 (int 'a') (int 'z') c
| c -> c
new string([| for c in text -> rotChar13 c|])

let rot47 (text:string) =
let rotChar47 = function
| ' ' as c -> c
| c -> rotChar 47 (int '!') (int '~') c
new string([| for c in text -> rotChar47 c |])

groovy

char rot13(s) {
char c = s
switch(c) {
case 'A'..'M': case 'a'..'m': return c+13
case 'N'..'Z': case 'n'..'z': return c-13
default : return c
}
}
String.metaClass.rot13 = {
delegate.collect(this.&rot13).join()
}

from = '!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~'
to = 'PQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO'
String.metaClass.rot47 = {
delegate.collect{ int found = from.indexOf(it); found < 0 ? it : to[found] }.join()
}

assert 'Hello World #123'.rot13() == 'Uryyb Jbeyq #123'
assert 'Hello World #123'.rot47() == 'w6==@ (@C=5 R`ab'

java

CharArrayWriter rot13 = new CharArrayWriter() ;
for (char c : i ) {
char lc = Character.toLowerCase(c) ;
rot13.append( c += ( (lc >= 'a' && lc <= 'm') ? 13 : ( (lc >= 'n' && lc <= 'z') ? -13 : 0 ) )) ;
}

CharArrayWriter rot47 = new CharArrayWriter() ;
for (char c : i )
rot47.append( c += ( (c >= '!' && c <= 'O') ? 47 : ( (c >= 'P' && c <= '~') ? -47 : 0 ) )) ;

Case

Make a string uppercase

Transform "Space Monkey" into "SPACE MONKEY"

ruby

uppper = text.upcase

erlang

io:format("~s~n", [string:to_upper("Space Monkey")]).

csharp

string output = "Space Monkey"

System.Console.WriteLine(output.ToUpper())

fsharp

printfn "%s" ("Space Monkey".ToUpper())

printfn "%s" (String.uppercase "Space Monkey")

groovy

println "Space Monkey".toUpperCase()

java

String upper = text.toUpperCase();

Make a string lowercase

Transform "Caps ARE overRated" into "caps are overrated"

ruby

"Caps ARE overRated".downcase

erlang

io:format("~s~n", [string:to_lower("Caps ARE overRated")]).

csharp

string str = "Caps ARE overRated";
str = str.ToLower() ;
Console.WriteLine(str);

fsharp

printfn "%s" ("Caps ARE overRated".ToLower())

printfn "%s" (String.lowercase "Caps ARE overRated")

groovy

println "Caps ARE overRated".toLowerCase()

java

"Caps ARE overRated".toLowerCase();

Capitalise the first letter of each word

Transform "man OF stEEL" into "Man Of Steel"

ruby

caps = text.gsub(/\w+/) { $&.capitalize }

caps = text.split.each{|i| i.capitalize!}.join(' ')

text.split.map(&:capitalize) * ' '

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());

fsharp

let words = String.Join(" ", Array.map (fun (s : String) -> (String.capitalize (s.ToLower()))) ("man OF stEEL".Split [|' '|]))

let wordlst = List.map (fun s -> (String.capitalize (String.lowercase s))) (String.split [' '] "man OF stEEL")
let words = new StringBuilder(List.hd wordlst)
for (s : String) in (List.tl wordlst) do (words.Append(" ").Append(s))

// Previous solutions used old library functions, here's something that works with F# 2.0
let s= "man OF stEEL"
let UpperFirst = function | "" -> "" | s -> s.Substring(0,1).ToUpper() + s.Substring(1).ToLower()
s.Split(' ') |> Array.map UpperFirst |> String.concat " "

let culture = System.Globalization.CultureInfo.GetCultureInfo("en-US")
let titleCase = culture.TextInfo.ToTitleCase "man oF sTeel"

groovy

def capitalize(s) { s[0].toUpperCase() + s[1..-1].toLowerCase() }
caps = "man OF stEEL".replaceAll(/\w+/) { w -> capitalize(w) }

caps = "man OF stEEL".replaceAll(/\w+/) { w -> StringUtils.capitalize(w.toLowerCase()) }

caps = WordUtils.capitalizeFully("man OF stEEL")

java

String input = "man OF stEEL";
StringTokenizer tokenizer = new StringTokenizer(input);
StringBuffer sb = new StringBuffer();
while (tokenizer.hasMoreTokens()) {
String word = tokenizer.nextToken();
sb.append(word.substring(0, 1).toUpperCase());
sb.append(word.substring(1).toLowerCase());
sb.append(' ');
}
String text = sb.toString();

StringBuilder sb = new StringBuilder("man OF stEEL"); String s = sb.toString();
int last = s.length() - 1;

for (int i = 0; i <= last; ++i)
if (Character.isSpaceChar(s.charAt(i)) && i < last) { ++i; sb.setCharAt(i, Character.toUpperCase(s.charAt(i))); }
else if (i == 0) sb.setCharAt(i, Character.toUpperCase(s.charAt(i)));
else sb.setCharAt(i, Character.toLowerCase(s.charAt(i)));

Matcher m = Pattern.compile("(\\w+)").matcher("man OF stEEL"); StringBuffer sb = new StringBuffer(32), rsb = new StringBuffer(8);

while (m.find())
{
rsb.replace(0, rsb.length(), m.group().toLowerCase()); rsb.setCharAt(0, Character.toUpperCase(rsb.charAt(0)));
m.appendReplacement(sb, rsb.toString());
}
m.appendTail(sb);

String text = WordUtils.capitalizeFully("man OF stEEL");