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preg_quoteQuote regular expression characters


preg_quote ( string $str [, string $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 that preg_quote() is not meant to be applied to the $replacement string(s) of preg_replace() etc.



The input string.


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.

Valorile întoarse

Returns the quoted (escaped) string.

Istoricul schimbărilor

Versiune Descriere
7.3.0 The # character is now quoted
5.3.0 The - character is now quoted


Example #1 preg_quote() example

'$40 for a g3/400';
$keywords preg_quote($keywords'/');
$keywords// returns \$40 for a g3\/400

Example #2 Italicizing a word within some text

// 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>",


Notă: Această funcție acceptă și date binare.

A se vedea și

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User Contributed Notes 5 notes

12 years ago
Wondering why your preg_replace fails, even if you have used preg_quote?

Try adding the delimiter / - preg_quote($string, '/');
11 years ago
To escape characters with special meaning, like: .-[]() and so on, use \Q and \E.

For example:

<?php echo ( preg_match('/^'.( $myvar = 'te.t' ).'$/i', 'test') ? 'match' : 'nomatch' ); ?>

Will result in: match


<?php echo ( preg_match('/^\Q'.( $myvar = 'te.t' ).'\E$/i', 'test') ? 'match' : 'nomatch' ); ?>

Will result in: nomatch
ed at happysoftware dot com
1 year ago
It should be noted that the forward slash is not escaped.  Since many regexes are surrounded by forward slashes, if you have one in your regex as  text you must escape it yourself otherwise it'll terminat the regex.
rwillmann at crooce dot com
3 years ago
List of specials is incomplete:

--- sample code ---

$specials = '.\+*?[^]$(){}=!<>|:-';

for ($i = 0; $i <= 255; $i++) {

    if (chr($i) !== preg_quote(chr($i))) {

        printf("Character 0x%02x quoted%s\n",
               (strpos($specials, chr($i)) === FALSE) ? ' (+)' : '');
    } /* if */
} /* for */

--- sample code ---

--- output ---

Character 0x00 quoted (+)
Character 0x21 quoted
Character 0x24 quoted
Character 0x28 quoted
Character 0x29 quoted
Character 0x2a quoted
Character 0x2b quoted
Character 0x2d quoted
Character 0x2e quoted
Character 0x3a quoted
Character 0x3c quoted
Character 0x3d quoted
Character 0x3e quoted
Character 0x3f quoted
Character 0x5b quoted
Character 0x5c quoted
Character 0x5d quoted
Character 0x5e quoted
Character 0x7b quoted
Character 0x7c quoted
Character 0x7d quoted

--- output ---
noreply at t-regx dot com
1 year ago
If you find yourself using too much of preg_quote(), it's a good sign you might want to use Prepared Patterns from T-Regx library:
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