How can i get sum of the values of an array where array index value starts with same value?

Question

Here are my two arrays.

This array is $assesment I have tried the code given below and got $cat_array.

    foreach($assesment as $k => $v){
    $k2 = explode("_",$k);
    /* echo "cat : ".$cat = $k2[0] ."-". $v;
    echo "<br>";
    echo "Que : ".$que = $k2[1]."-". $v;
    echo "<br>"; */
    $cat_array[] = $k2[0]."-".$v;   
    }
print_r($cat_array);

Answer 1

Just update your loop like as

$cat_array = array();
foreach($assesment as $k => $v){
    $k2 = explode("_",$k);
    if(isset($cat_array[$k2[0]])){
        $cat_array[$k2[0]] += $v;
    }else{
        $cat_array[$k2[0]] = $v;
    }
}