The preg_replace Function

The preg_replace function searches a string for matches with a regular expression and replaces them with the specified string. The first parameter accepts the regular expression for the search, the second - the replacement string, the third - the source string. Additionally, you can specify a replacement limit and a variable for counting replacements.

Syntax

preg_replace(pattern, replacement, subject, [limit], [count]);

Example

Let's replace all digits in the string with the character 'X':

<?php
	$str = 'a1b2c3';
	$res = preg_replace('/\d/', 'X', $str);
	echo $res;
?>

Code execution result:

'aXbXcX'

Example

Let's replace only the first 2 matches:

<?php
	$str = 'a1b2c3';
	$res = preg_replace('/\d/', 'X', $str, 2);
	echo $res;
?>

Code execution result:

'aXbXc3'

Example

Using backreferences in replacement:

<?php
	$str = 'Hello World';
	$res = preg_replace('/(\w+)\s(\w+)/', '$2, $1', $str);
	echo $res;
?>

Code execution result:

'World, Hello'

Example

Counting the number of replacements performed:

<?php
	$str = 'a1b2c3';
	$count = 0;
	$res = preg_replace('/\d/', 'X', $str, -1, $count);
	echo "Result: $res, Replacements: $count";
?>

Code execution result:

'Result: aXbXcX, Replacements: 3'

The preg_replace Function

Syntax

Example

Example

Example

Example

See Also