data = [
 {
    "Payment_type":1,
    "amount":10000
 },

 {
    "Payment_type":1,
    "amount":40000
 },
 {
    "Payment_type":2,
    "amount":10000
 },
 {
    "Payment_type":2,
    "amount":20000
 }

Payment type 1
       ---10000
       ---40000
   Payment type 2
       ---10000
       ---20000

foreach($data as $d)
   {
       if($d->Payment_type == 1)
       {
           echo $d->amount;
       }
       else
       {
           echo $d->amount;
       }
   }

function groupArray($arr, $group, $preserveSubArrays = false, $preserveGroupKey = false) {
    $temp = array();
    foreach($arr as $key => $subarray) {
        $groupBy = $subarray[$group];
        if(!$preserveGroupKey) {
            unset($arr[$key][$group]);
        }
        if(!array_key_exists($groupBy, $temp)) {
            $temp[$groupBy] = array();
        }
        if(!$preserveSubArrays && count($arr[$key])==1) {
            $temp[$groupBy][] = current($arr[$key]);
        } else {
            $temp[$groupBy][] = $arr[$key];
        }
    }
    return $temp;
}

print_r(groupArray($data, "Payment_type", false, false));

Array
(
    [1] => Array
        (
            [0] => 10000
            [1] => 40000
        )

    [2] => Array
        (
            [0] => 10000
            [1] => 20000
        )

)