array_intersect_ukey Computes the intersection of arrays using a callback function on the keys for comparison &reftitle.description; arrayarray_intersect_ukey arrayarray1 arrayarray2 array... callablekey_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. &reftitle.parameters; array1 Initial array for comparison of the arrays. array2 First array to compare keys against. ... Variable list of array arguments to compare keys against. key_compare_func &return.callbacksort; &callback.cmp; &reftitle.returnvalues; Returns the values of array1 whose keys exist in all the arguments. &reftitle.examples; $key2) return 1; else return -1; } $array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4); $array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan' => 8); var_dump(array_intersect_ukey($array1, $array2, 'key_compare_func')); ?> ]]> &example.outputs; int(1) ["green"]=> int(3) } ]]> 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. &reftitle.seealso; array_diff array_udiff array_diff_assoc array_diff_uassoc array_udiff_assoc array_udiff_uassoc array_diff_key array_diff_ukey array_intersect array_intersect_assoc array_intersect_uassoc array_intersect_key