(PHP 5 >= 5.1.0, PHP 7, PHP 8)
array_diff_ukey — Computes the difference of arrays using a callback function on the keys for comparison
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.
Unlike array_diff_key() a user supplied callback function is used for the indices comparison, not internal function.
arrayThe array to compare from
arraysArrays to compare against
key_compare_funcThe comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.
Returning non-integer values from the comparison
function, such as float, will result in an internal cast to
int of the callback's return value. So values such as
0.99 and 0.1 will both be cast to an
integer value of 0, which will compare such values as equal.
Returns an array containing all the entries from
array that are not present in any of the other arrays.
Example #1 array_diff_ukey() example
<?php
function key_compare_func($key1, $key2)
{
if ($key1 == $key2)
return 0;
else if ($key1 > $key2)
return 1;
else
return -1;
}
$array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan' => 8);
var_dump(array_diff_ukey($array1, $array2, 'key_compare_func'));
?>
The above example will output:
array(2) {
["red"]=>
int(2)
["purple"]=>
int(4)
}
Note:
This function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using
array_diff_ukey($array1[0], $array2[0], 'callback_func');.