PHP array_intersect + array_flip with array that has values multiple times

Question

I have two arrays:

$arr1 = array(101 => 250, 102 => 250, 103 => 250, 104 => 500, 105 => 500, 106 => 500,);

and

Answer 1

The following code does the job. I hope it is self-explanatory.

array_unique(array_intersect_key($arr1, array_flip($arr2)))