PHP functions to test if an array is associative or numeric (hash vs array)

php-array-tests.php

/**
* Returns boolean if a function is an associative array
*
* @param array $array An array to test
*
* @return boolean
*/
public static function is_assoc_array($array) {
	if (!is_array($array)) { return false; }
	// $array = array() is not associative
	if (sizeof($array) === 0) { return false; }

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

/**
* Returns boolean if a function is flat/sequential numeric array
*
* @param array $array An array to test
*
* @return boolean
*/
public static function is_numeric_array($array) {
	if (!is_array($array)) { return false; }

	$current = 0;
	foreach (array_keys($array) as $key) {
		if ($key !== $current) { return false; }

		$current++;
	}

	return true;
}