PHP check for array type

is_assoc.php

<?php

/**
 * Check to see if the supplied array is associative.
 * 
 * @link http://stackoverflow.com/questions/173400/how-to-check-if-php-array-is-associative-or-sequential
 * @return bool True if is associative, false if non-associative.
 */
function is_assoc($array) {
  return (bool)count(array_filter(array_keys($array), 'is_string'));
}