PHP preg_replace() function

Author：Eve Cole Update Time：2024-12-28 12:00:02

The preg_replace function performs a regular expression search and replace.

grammar

 mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )

Search the part of subject that matches pattern and replace it with replacement.

Parameter description:

$pattern: The pattern to search for, which can be a string or an array of strings.

$replacement: String or array of strings to use for replacement.

$subject: The target string or string array to be searched and replaced.

$limit: Optional, the maximum number of substitutions for each subject string per pattern. The default is -1 (no limit).

$count: Optional, the number of times the replacement is performed.

return value

If subject is an array, preg_replace() returns an array, otherwise it returns a string.

If a match is found, the replaced subject is returned, otherwise the unchanged subject is returned. If an error occurs, NULL is returned.

Example

Replace google with codecto

<?php $string = ' google 123, 456 ' ; $pattern = ' /(w+) (d+), (d+)/i ' ; $replacement = ' codercto ${2},$3 ' ; echo preg_replace ( $pattern , $replacement , $string ) ; ?>

The execution result is as follows:

 codercto 123,456

Remove space characters

<?php $str = ' runo ob ' ; $str = preg_replace ( ' /s+/ ' , ' ' , $str ) ; // will be changed to 'codercto' echo $str ; ?>

The execution result is as follows:

 codercto

Using array index based search and replace

<?php $string = ' The quick brown fox jumped over the lazy dog. ' ; $patterns = array ( ) ; $patterns [ 0 ] = ' /quick/ ' ; $patterns [ 1 ] = ' /brown/ ' ; $patterns [ 2 ] = ' /fox/ ' ; $replacements = array ( ) ; $replacements [ 2 ] = ' bear ' ; $replacements [ 1 ] = ' black ' ; $replacements [ 0 ] = ' slow ' ; echo preg_replace ( $patterns , $replacements , $string ) ; ?>

The execution result is as follows:

 The bear black slow jumped over the lazy dog.

Use parameter count

<?php $count = 0 ; echo preg_replace ( array ( ' /d/ ' , ' /s/ ' ) , ' * ' , ' xp 4 to ' , - 1 , $count ) ; echo $count ; // 3 ?>

The execution result is as follows:

 xp***to3