preg_filter
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
preg_filter — Perform a regular expression search and replace
Description
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.
Parameters
Parameters are described in the documentation for preg_replace().
Return Values
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.
Errors/Exceptions
If the regex pattern passed does not compile to a valid regex, an E_WARNING is emitted.
Examples
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
)
See Also
- PCRE Patterns
- preg_quote() - Quote regular expression characters
- preg_replace() - Perform a regular expression search and replace
- preg_replace_callback() - Perform a regular expression search and replace using a callback
- preg_grep() - Return array entries that match the pattern
- preg_last_error() - Returns the error code of the last PCRE regex execution
