php - Create an array from two associative array -

i've 2 arrays bellow:

array (size=2)   827 => int 3   868 => int 3   array (size=4)   827 => int 2   868 => int 2   829 => int 1   541 => int 1 

i want combine 2 arrays , add values when keys matches. resulting array needs be:

array (size=4)   827 => int 5   868 => int 5   829 => int 1   541 => int 1 

tried different array manipulation function none of them worked. appreciated.

you can following: using + on arrays, creating new array, have key/values of both, duplicates not overriden second one. after can loop again on second array , and add values (but if value not present in $a1). if not present in $a1, value in merged array $a2.

$a1 = array(827 => 3, 868 => 3); $a2 = array(827 => 2, 868 => 2, 829 => 1, 541 => 1);  $merged = $a1+$a2;  foreach($a2 $key => $value){     if(!empty($a1[$key])){         $merged[$key] = $merged[$key] + $value;     } }