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Computes the intersection of arrays using a callback function on the keys for comparison (PHP 5 >= 5.1.0)
array array_intersect_ukey ( array array1, array array2 [, array ..., callback key_compare_func] )

array_intersect_ukey() returns an array containing all the values of array1 which have matching keys that are present in all the arguments.

This comparison is done by a user supplied callback function. It must return an integer less than, equal to, or greater than zero if the first key is considered to be respectively less than, equal to, or greater than the second.



Initial array for comparision of the arrays.


First array to compare keys against.


Variable list of array arguments to compare keys against.


User supplied callback function to do the comparision.

Return Values

Returns the values of array1 whose keys exist in all the arguments.


Example 252. array_intersect_ukey() example

function key_compare_func($key1, $key2)
   if (
$key1 == $key2)
   else if (
$key1 > $key2)
       return -

$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'   => 8);

var_dump(array_intersect_ukey($array1, $array2, 'key_compare_func'));

The above example will output:

array(2) {

In our example you see that only the keys 'blue' and 'green' are present in both arrays and thus returned. Also notice that the values for the keys 'blue' and 'green' differ between the two arrays. A match still occurs because only the keys are checked. The values returned are those of array1.