(PHP 5 >= 5.1.0, PHP 7)
array_diff_key — Computes the difference of arrays using keys for comparison
array_diff_key ( array $array , array ...$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.
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]);.
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https://www.php.net/manual/en/function.array-diff-key.php