find the mode of an array using PHP

mode.php

function array_mode($$arr) {
  /*
  Count the frequency of occurrence of values in the array.
  This will make each duration value into a key, with its frequency as the
  value
  */
  $counts = array_count_values($$arr);

  /*
    Get all of the count values and find the unique values, then sort them,
    highest to lowest. This gives us the highest count value.
  */
  $freq = array_unique($counts);
  arsort($freq);

  // Grab the maximum frequency value, which will be the first one.
  $max = array_shift($freq);

  // Returns items in $counts that match this max value.
  $max_match = array_filter($counts, function($dur) use ($max) {
    return $dur === $max;
  });
  
  // Remember durations are the keys!
  $mode = array_keys($max_match);

  // If the array is multimodal, return the whole thing. Otherwise, return first one. 
  return (count($mode) > 1) ? $mode : $mode[0];
}