(PHP 5 >= 5.3.0, PHP 7)
preg_filter — Perform a regular expression search and replace
preg_filter ( string|array $pattern , string|array $replacement , string|array $subject [, int $limit = -1 [, int &$count = null ]] ) : string|array|null
preg_filter() is identical to preg_replace() except it only returns the (possibly transformed) subjects where there was a match. For details about how this function works, read the preg_replace() documentation.
Returns an array if the subject parameter is an array, or a string otherwise.
If no matches are found or an error occurred, an empty array is returned when subject is an array or null otherwise.
Example #1 Example comparing preg_filter() with preg_replace()
<?php
$subject = array('1', 'a', '2', 'b', '3', 'A', 'B', '4');
$pattern = array('/\d/', '/[a-z]/', '/[1a]/');
$replace = array('A:$0', 'B:$0', 'C:$0');
echo "preg_filter returns\n";
print_r(preg_filter($pattern, $replace, $subject));
echo "preg_replace returns\n";
print_r(preg_replace($pattern, $replace, $subject));
?> The above example will output:
preg_filter returns
Array
(
[0] => A:C:1
[1] => B:C:a
[2] => A:2
[3] => B:b
[4] => A:3
[7] => A:4
)
preg_replace returns
Array
(
[0] => A:C:1
[1] => B:C:a
[2] => A:2
[3] => B:b
[4] => A:3
[5] => A
[6] => B
[7] => A:4
)
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https://www.php.net/manual/en/function.preg-filter.php