(PHP 4 CVS only)array_intersect_assoc -- Computes the intersection of arrays with additional index check
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().
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 it's key is 2 while the key of "red" in $array2 it is 1.
The two values from the key => value pairs are considered equal only if (string) $elem1 === (string) $elem2 . In otherwords a strict type check is executed so the string representation must be the same.