langref.org - ruby and erlang

View Category

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").

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, "&"),...

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]).

Declaration

Define a string containing special characters

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

ruby

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

erlang

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",

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)]).

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"),

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!", " ")), " "),

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")).

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),

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).

Case