Php/docs/function.preg-quote
preg_quote
(PHP 4, PHP 5, PHP 7)
preg_quote — Quote regular expression characters
Description
preg_quote
( string $str
[, string|null $delimiter
= NULL
] ) : string
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:
. \ + * ? [ ^ ] $ ( ) { } = ! < > | : - #
Note that /
is not a special regular expression character.
Note:
Note that preg_quote() is not meant to be applied to the $replacement string(s) of preg_replace() etc.
Parameters
str
- The input string.
delimiter
- If the optional
delimiter
is specified, it will also be escaped. This is useful for escaping the delimiter that is required by the PCRE functions. The/
is the most commonly used delimiter.
Return Values
Returns the quoted (escaped) string.
Changelog
Version | Description |
---|---|
7.3.0 | The # character is now quoted
|
7.2.0 | delimiter is nullable now.
|
Examples
Example #1 preg_quote() example
<?php$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 isbinary-safe.