如何获得数组值的总和，其中数组索引值以相同的值开始？

Here are my two arrays.

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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);

enter image description here

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;
    }
}