As shown in the pseudocode, we will have two functions to implement a quick sort: one function to do the quick sort itself, and the other for the partitioning. Here is the implementation to do the quick sort:

function quickSort(array &$arr, int $p, int $r) {
  if($p < $r) {
    $q = partition($arr, $p, $r);
    quickSort($arr, $p, $q);
    quickSort($arr, $q+1, $r);
  }
}

Here is the implementation to do the partitioning:

function partition(array &$arr, int $p, int $r){ 
  $pivot = $arr[$p]; 
  $i = $p-1; 
  $j = $r+1; 
  while(true) 
  { 
   do { 
    $i++; 
   } while($arr[$i] < $pivot && $arr[$i] != $pivot); 
   do { 
    $j--; 
   } while($arr[$j] > $pivot && $arr[$j] != $pivot); 

   if($i < $j) { 
    $temp = $arr[$i]; 
    $arr[$i] = $arr[$j]; 
    $arr[$j] = $temp; 
   } else { 
    return $j; 
      } 
  } 
}

 $arr = [20, 45, 93, 67, 10, 97, 52, 88, 33, 92]; 

quickSort($arr, 0, count($arr)-1); 
echo implode(",", $arr);

If we visually illustrate the pivot and the sorting in the partitions, we can see the following image. For simplicity, we are only showing the steps where swapping took place: