array_intersect_assoc Computes the intersection of arrays with additional index check arrayarray_intersect_assoc arrayarray1 arrayarray2 array ... array_intersect_assoc returns an array containing all the values of array1 that are present in all the arguments. Note that the keys are used in the comparison unlike in array_intersect. "green", "b" => "brown", "c" => "blue", "red"); $array2 = array("a" => "green", "yellow", "red"); $result_array = array_intersect_assoc($array1, $array2); ?> ]]> $result_array will look like: green ) ]]> In our example you see that only the pair "a" => "green" is present in both arrays and thus is returned. The value "red" is not returned because in $array1 its key is 0 while the key of "red" in $array2 is 1. The two values from the key => value pairs are considered equal only if (string) $elem1 === (string) $elem2 . In other words a strict type check is executed so the string representation must be the same. See also array_intersect, array_uintersect_assoc, array_intersect_uassoc, array_uintersect_uassoc, array_diff and array_diff_assoc.