Core Function Regex Replace

Revision as of 00:11, 18 January 2013

<Expression> =~ s/pattern/replacement/flags

Description

Replace parts of a string using a regular expression pattern and optionally executing functions on the matched groups

Parameters

Expression

Any valid expression that is a string.

pattern

The regular expression pattern to match.

pattern

A string to replace the match(es) with.

flags

Optional; The flags to use in the pattern.

i = Ignore case.

m = Treat the string as multiple lines.

s = Treat the string as a single line.

o = Do not recompile the regular expression after the first compile (Improves speed of your matches if you run the pattern many times).

g = Match all occurrences of the pattern in the string (Default is only match the first).

e = Treat the replace string as actual Sputnik code similar to Eval().

Return Value

Success: Returns the modified string.

Failure: Returns an empty string.

Remarks

See regex match for details on regex.

Example

A simple search replace

// A string to use
$var = "That cat is cute but this cat is not";
 
// Replace cat with dog
$var =~ s/cat/dog/;
 
println( $var );

Same again but this time replace all using the "g" switch

// A string to use
$var = "That cat is cute but this cat is not";
 
// Replace cat with dog
$var =~ s/cat/dog/g;
 
println( $var );

Same again but this time ignore case using the "i" switch

// A string to use
$var = "That cat is cute but this Cat is not";
 
// Replace cat with dog
$var =~ s/cat/dog/gi;
 
println( $var );

Search the string and reverse the order so stuff after the = now comes before it

// A string to use
$var =  "One=100\n";
$var .= "Two=200\n";
$var .= "Three=300\n";
 
$var =~ s/(\w+)=(\w+)/$2=$1/gi;
 
println( $var );

Execute the replace as a function using the "e" switch and increase all numbers in the string by 1

// A string to use
$var =  "10 20 30 40 50 60 70 80 90 100";
 
$var =~ s/(\d+)/$1++/egi;
 
println( $var ); // Prints 11 21 31 41 51 61 71 81 91 101

Execute the replace as a function using the "e" switch and increase all numbers in the string by 1 and move all the letters to the end instead of beginning of each section

// A string to use
$var =  "A:10 B:20 C:30 D:40 E:50 F:60 G:70 H:80 I:90 J:100";
 
$var =~ s/(\w):(\d+)/Action($1, $2)/egi;
 
println( $var ); // Prints 11:A 21:B 31:C 41:D 51:E 61:F 71:G 81:H 91:I 101:J
 
// Define a function to use for the regex
Function Action( $Letter, $Number )
{
	// Move to letter to end and increase the number by 1
	return ($Number++) . ":" . $Letter;
}

Take a string containing floating point numbers and convert them to integers using floor()

// A string to use
$var =  "10.2 300.45 133.77";
 
$var =~ s/(\d+\.\d*)/floor($1)/egi; // Prints 10 300 133
 
println( $var );

Convert a string to hex and back again using switch "e" on a regex to decode the hex

$hex = Unpack("*H", "Hello World!", 1);
println("Hex String: " . $hex);
$hex =~ s/([\dA-Fa-f][\dA-Fa-f])/Chr(Dec($1))/ego;
println("Normal String: " . $hex);

Here we use regex to decode a QUERY_STRING and resolve the key, values into a hashmap Request[]

Global $Request = array();
{
	$QueryString = EnvGet("QUERY_STRING");
	$QueryList = Split($QueryString, '&');
	Foreach($QueryList as $i)
	{
		List ( $Key, $Value ) = Split($i, '=');
		$Value =~ s/%([a-fA-F0-9][a-fA-F0-9])/Chr(Dec($1))/ego;
		$Value =~ s/\+/ /gi; 
		$Value =~ s/\</&lt;/gi; 
		$Value =~ s/\>/&gt;/gi; 
		$Request[$Key] = $Value;
	}
}