$pro1 = [];
$pro2 = [1=>1, 3=>'вася'];
$diff = array_diff($pro1,$pro2);
array array_diff ( array $array1 , array $array2 [, array $... ] )php.net/manual/en/function.array-diff.php
Compares array1 against one or more other arrays and returns the values in array1 that are not present in any of the other arrays.