PHP Manual: Computes the difference of arrays using a callback function on the keys for comparison

Description

array array_diff_ukey ( array $array1 , array $array2 [, array $... ], callable $key_compare_func )

Compares the keys from array1 against the keys from array2 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.

Parameters

array1: The array to compare from
array2: An array to compare against
...: More arrays to compare against
key_compare_func: The 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. Note that before PHP 7.0.0 this integer had to be in the range from -2147483648 to 2147483647.

int callback ( mixed $a, mixed $b )

Return Values

Returns an array containing all the entries from array1 that are not present in any of the other arrays.

Examples

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)
}

Notes

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');.

array_diff_ukey

Description

Parameters

Return Values

Examples

Notes

See Also