PCRE Functions
Another way to filter an array, and simply return the matching items: preg_grep!
preg_filter
(PHP 5 >= 5.3.0)
preg_filter — Perform a regular expression search and replace
Description
mixed preg_filter
( mixed
$pattern
, mixed $replacement
, mixed $subject
[, int $limit = -1
[, int &$count
]] )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.
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.
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, $subject));
?>
The above example will output:
preg_filter returns
Array
(
[0] => A:C:1
[1] => B:C:a
[2] => A:2
[3] => B:b
[4] => A:3
[7] => A:4
)
preg_replace returns
Array
(
[0] => A:C:1
[1] => B:C:a
[2] => A:2
[3] => B:b
[4] => A:3
[5] => A
[6] => B
[7] => A:4
)
See Also
- PCRE Patterns
- preg_replace() - Perform a regular expression search and replace
- preg_replace_callback() - Perform a regular expression search and replace using a callback
- preg_grep() - Return array entries that match the pattern
- preg_last_error() - Returns the error code of the last PCRE regex execution
add a note
User Contributed Notes
preg_filter - [3 notes]
MrBertie ¶
2 years ago
sajina_99 at hotmail dot de ¶
1 year ago
As I had to work with PHP5.2.X and needed preg_filter I wrote a quick and dirty workaround.
<?php
if (!function_exists('preg_filter')) {
function preg_filter($pattern, $replace, $subject, $limit = -1 , &$count = null) {
if(!is_array($subject)) {
$noArray = 1 ;
$subject = array($subject);
}
$preg = preg_replace($pattern, $replace, $subject, $limit, &$count);
$diff = array_diff($preg, $subject);
if($noArray == 1) $diff = implode($diff) ;
return $diff ;
}
}
?>
Eric Naeseth ¶
2 years ago
If you want to just filter an array based on a regular expression, without replacing any of the array values, try RegexIterator: http://us3.php.net/manual/en/class.regexiterator.php