(PHP 5 >= 5.1.0, PHP 7, PHP 8)
array_diff_key — Computes the difference of arrays using keys for comparison
$array
, array ...$arrays
): array
Compares the keys from array
against the keys
from arrays
and returns the difference.
This function is like array_diff() except the
comparison is done on the keys instead of the values.
array
The array to compare from
arrays
Arrays to compare against
Returns an array containing all the entries from
array
whose keys are absent from all of the
other arrays.
Version | Description |
---|---|
8.0.0 | This function can now be called with only one parameter. Formerly, at least two parameters have been required. |
Example #1 array_diff_key() example
The two keys from the key => value
pairs are
considered equal only if
(string) $key1 === (string) $key2
. In other words
a strict type check is executed so the string representation must be
the same.
<?php
$array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4);
$array2 = array('green' => 5, 'yellow' => 7, 'cyan' => 8);
var_dump(array_diff_key($array1, $array2));
?>
The above example will output:
array(3) { ["blue"]=> int(1) ["red"]=> int(2) ["purple"]=> int(4) }
<?php
$array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4);
$array2 = array('green' => 5, 'yellow' => 7, 'cyan' => 8);
$array3 = array('blue' => 6, 'yellow' => 7, 'mauve' => 8);
var_dump(array_diff_key($array1, $array2, $array3));
?>
The above example will output:
array(2) { ["red"]=> int(2) ["purple"]=> int(4) }
Note:
This function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using
array_diff_key($array1[0], $array2[0]);
.