Find anagram from given array

question_3.php

<?php

function findAnagrams($dict)
{
  $anagrams   = [];
  $_sortString  = function ($str) {
    $l = str_split($str);
    sort($l);

    return implode('', $l);
  };

  foreach ($dict as $word)
  {
    $index = $_sortString($word);
    $anagrams[$index][] = $word;
  }

  return array_filter($anagrams, function ($el) {
    return count($el) > 1;
  });
}

$dict = ["bat", "code", "cat", "act", "cab", "crazy", "tac"];
print_r(findAnagrams($dict));