PHP get array_diff key

Question

Array1:

array('13','15','19');

Array2:

array('13','19');

Expected output:

2

Program:

$array1 = array('13','15','19');
$array2 = array('13','19');
print_r(array_diff($array1, $array2));

array_diff giving me value which value is different but instead it I want key. How can I get key?

Answer 1

I think you're looking for :

$array1 = array('13','15',17,'19',21);
$array2 = array('13','19');
print_r(array_keys(array_diff($array1, $array2)));

which will print you 1,2 and 4 - the keys. (remember "1" means second, because we're starting with 0 key)