preg_match
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
But:
<?php echo ( preg_match('/^\Q'.( $myvar = 'te.t' ).'\E$/i', 'test') ? 'match' : 'nomatch' ); ?>
Will result in: nomatch
preg_quote
(PHP 4, PHP 5)
preg_quote — Protection des caractères spéciaux des expressions rationnelles
Description
string preg_quote
( string $str
[, string $delimiter= NULL
] )
preg_quote() ajoute un antislash devant tous les caractères de la chaîne str . Cela est très utile si vous avez une chaîne qui va servir de masque, mais qui est générée durant l'exécution.
Les caractères spéciaux qui seront protégés sont les suivants : . \ + * ? [ ^ ] $ ( ) { } = ! < > | : -
Liste de paramètres
- str
-
La chaîne d'entrée.
- delimiter
-
Si l'argument optionnel delimiter est fourni, il sera aussi échappé. Ceci est pratique pour échapper le délimiteur requis par les fonctions PCRE. Le slash / est le délimiteur le plus répandu.
Valeurs de retour
Retourne la chaîne protégée.
Historique
| Version | Description |
|---|---|
| 5.3.0 | Le caractère - est maintenant protégé. |
Exemples
Exemple #1 Exemple avec preg_quote()
<?php
$keywords = '$40 pour un g3/400';
$keywords = preg_quote($keywords, '/');
echo $keywords; // retourne \$40 pour un g3\/400
?>
Exemple #2 Mise en italique d'un mot dans un texte
<?php
// Dans cet exemple, preg_quote($word) sert à éviter que les astérisques
// prennent une valeur particulière dans l'expression rationnelle.
$textbody = "Ce livre est *très* difficile à trouver.";
$word = "*très*";
$textbody = preg_replace ("/" . preg_quote($word) . "/",
"<i>" . $word . "</i>",
$textbody);
?>
Notes
Note: Cette fonction gère les chaînes binaires.
add a note
User Contributed Notespreg_quote
zooly
21-Jul-2009 08:07
21-Jul-2009 08:07
alexc223 at NOSPAM dot googlemail dot com
15-Jun-2009 07:41
15-Jun-2009 07:41
Not sure why this note got deleted, but hey lets try again:
As of PHP 5.3, bug #47229 has been fixed and preg_quote *will* escape a hyphen (-). This may effect your code so ensure this is one thing you check when moving to 5.3.
frostschutz
20-Mar-2009 10:01
20-Mar-2009 10:01
I wanted to escape a string of characters so I could match them in [], i.e. [.,-!"§$%\\\[\]\^].
Unfortunately preg_quote does not escape the - character which has a special meaning in [], i.e. [a-z].
So I used this hack: make - the delimiter of the expression, i.e.
preg_quote(userinput, "-")
preg_replace("-[$userinput]-u", "", $str)
Apparently using a special char as a delimiter of a regular expression disables this character, i.e. even if it's escaped it's not understood as special character for the expression anymore.
so the pattern "-[a\\-z]-u" matches the characters a, - and z, and not abc...xyz.
It would be nice if preg_quote also escaped characters that have special meanings even if they have this meaning only under certain conditions, such as inside [].
krishoog at gmail dot com
13-Oct-2008 02:51
13-Oct-2008 02:51
To bizzigul at hotmail dot fr:
It's not a good practice to make somthing work *almost* all of the time. If the input contains a '`' you will still get an error. I recommend using the default delimiter ('/') and also feed this to preg_quote as second argument.
bizzigul at hotmail dot fr
30-Jul-2008 04:10
30-Jul-2008 04:10
To prevent any problems, try to always use a delimiter that will *almost* not be used inside the regex, such as ` (back quote)
for example: instead of
<?php preg_match('/foo\/bar\//',$somevar); ?>
use
<?php preg_match('`foo/bar/`',$somevar); ?>
it's that simple! like this, you won't have to bother with delimiters anymore...
Anonymous
26-Dec-2007 11:13
26-Dec-2007 11:13
Wondering why your preg_replace fails, even if you have used preg_quote?
Try adding the delimiter / - preg_quote($string, '/');