Perform a regular expression search and replace using callbacks

Description

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

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

Parameters

pattern: An associative array mapping patterns (keys) to callables (values).
subject: The string or an array with strings to search and replace.
limit: The maximum possible replacements for each pattern in each subject string. Defaults to -1 (no limit).
count: If specified, this variable will be filled with the number of replacements done.
flags: 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 Values

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.

Errors/Exceptions

If the regex pattern passed does not compile to a valid regex, an E_WARNING is emitted.

Changelog

Version	Description
7.4.0	The `flags` parameter was added.

Examples

Example #1 preg_replace_callback_array() example


<?php
$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
);
?>

The above example will output:

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

preg_replace_callback_array