preg_replace_callback_array()

preg_replace_callback_array() — Perform a regular expression search and replace using callbacks.

Built-in function of PHP 8.5. The manual lists it as available in PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

The behavior of this function is similar to preg_replace_callback(), except that callbacks are executed on a per-pattern basis.

Signature

preg_replace_callback_array(array $pattern, string|array $subject, int $limit = -1, int &$count = null, int $flags = 0): string|array|null

Parameters

Parameter	Type	What it takes
$pattern	array	An associative array mapping patterns (keys) to callables (values).
$subject	string\|array	The string or an array with strings to search and replace.
$limit	int	The maximum possible replacements for each pattern in each subject string. Defaults to -1 (no limit).
&$count	int	If specified, this variable will be filled with the number of replacements done.
$flags	int	flags can be a combination of the PREG_OFFSET_CAPTURE and PREG_UNMATCHED_AS_NULL flags, which influence the format of the matches array. See the description in preg_match() for more details.

Return value

preg_replace_callback_array() returns an array if the subject parameter is an array, or a string otherwise. On errors the return value is null If matches are found, the new subject will be returned, otherwise subject will be returned unchanged.

Example

A runnable snippet:

$subject = 'Aaaaaa Bbb'; preg_replace_callback_array( [ '~[a]+~i' => function ($match) { echo strlen($match[0]), ' matches for "a" found', PHP_EOL; }, '~[b]+~i' => function ($match) { echo strlen($match[0]), ' matches for "b" found', PHP_EOL; } ], $subject );

Output:

6 matches for "a" found 3 matches for "b" found

Changelog

Version	Change
7.4.0	The flags parameter was added.