preg_filter
Run a match on the array's keys rather than the values:
<?php
function preg_grep_keys( $pattern, $input, $flags = 0 )
{
$keys = preg_grep( $pattern, array_keys( $input ), $flags );
$vals = array();
foreach ( $keys as $key )
{
$vals[$key] = $input[$key];
}
return $vals;
}
?>
preg_grep
(PHP 4, PHP 5)
preg_grep — Return array entries that match the pattern
Description
array preg_grep
( string $pattern
, array $input
[, int $flags = 0
] )
Returns the array consisting of the elements of the input array that match the given pattern.
Parameters
- pattern
-
The pattern to search for, as a string.
- input
-
The input array.
- flags
-
If set to PREG_GREP_INVERT, this function returns the elements of the input array that do not match the given pattern.
Return Values
Returns an array indexed using the keys from the input array.
Changelog
| Version | Description |
|---|---|
| 4.2.0 | The flags parameter was added. |
| 4.0.4 |
Prior to this version, the returned array was indexed regardless of the keys of the input array. If you want to reproduce this old behavior, use array_values() on the returned array to reindex the values. |
Examples
Example #1 preg_grep() example
<?php
// return all array elements
// containing floating point numbers
$fl_array = preg_grep("/^(\d+)?\.\d+$/", $array);
?>
See Also
- PCRE Patterns
- preg_match_all() - Perform a global regular expression match
- preg_filter() - Perform a regular expression search and replace
- preg_last_error() - Returns the error code of the last PCRE regex execution
add a note
User Contributed Notes
preg_grep
keithbluhm at gmail dot com
21-Jan-2010 03:56
pete dakin at aargh dot doh!
20-Nov-2008 07:24
<?php
/**
* Return the element key for a found pattern in an array
*
* @param String pattern
* @param Array input
* @return mixed
*/
function preg_array_key( $sPattern, $aInput ){
return key( preg_grep( $sPattern, $aInput ) );
}
?>
brian at cristina dot org
02-Sep-2008 01:31
I don't see it mentioned here but you can invert your match to only return array entries where the search values IS NOT found. The format for it is...
<?php
$nomatch = preg_grep("/{$keyword}/i",$array,PREG_GREP_INVERT);
?>
Notice the PREG_GREP_INVERT.
That will result in an array ($nomatch) that contains all entries of $array where $keyword IS NOT found.
Hope that helps!
-b