Test an array to see if an associative array (returns true), or a numerically indexed array (returns false)

isAssoc.php

<?php

# From Stack Overflow
# http://stackoverflow.com/questions/173400/how-to-check-if-php-array-is-associative-or-sequential

function isAssoc($array) {
  return array_keys($array) !== range(0, count($array) - 1);
}