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preg_replace_callback> <preg_match
Last updated: Fri, 16 May 2008

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preg_quote

(PHP 4, PHP 5)

preg_quote — Quote regular expression characters

Description

string preg_quote ( string $str [, string $delimiter ] )

preg_quote() takes str and puts a backslash in front of every character that is part of the regular expression syntax. This is useful if you have a run-time string that you need to match in some text and the string may contain special regex characters.

The special regular expression characters are: . \ + * ? [ ^ ] $ ( ) { } = ! < > | :

Parameters

str

The input string.

delimiter

If the optional delimiter is specified, it will also be escaped. This is useful for escaping the delimiter that is required by the PCRE functions. The / is the most commonly used delimiter.

Return Values

Returns the quoted string.

Examples

Example #1 preg_quote() example

<?php
$keywords 
'$40 for a g3/400';
$keywords preg_quote($keywords'/');
echo 
$keywords// returns \$40 for a g3\/400
?>

Example #2 Italicizing a word within some text

<?php
// In this example, preg_quote($word) is used to keep the
// asterisks from having special meaning to the regular
// expression.

$textbody "This book is *very* difficult to find.";
$word "*very*";
$textbody preg_replace ("/" preg_quote($word) . "/",
                          
"<i>" $word "</i>",
                          
$textbody);
?>

Notes

Note: This function is binary-safe.



add a note add a note User Contributed Notes
preg_quote
Anonymous
26-Dec-2007 03:13
Wondering why your preg_replace fails, even if you have used preg_quote?

Try adding the delimiter / - preg_quote($string, '/');

preg_replace_callback> <preg_match
Last updated: Fri, 16 May 2008
 
 
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