欧几里得度量（euclidean metric）二维

EuclidDistance.php

<?php
// 欧几里得度量_百度百科 http://baike.baidu.com/link?url=zAEZl46AoeKqIg0v1n_nPWP5JycEYvoOepRf_lTin_i-nb9YTNQGOFILLYYqTxF3Nho0Wn5vWgNWTYHklq0mE_
function distance()
{
	$argv = func_get_args();
	$argc = func_num_args();
	if ($argc !== sizeof($argv)) return;
	
	$res = $j = intval(NULL);
	for (; $j < sizeof($argv[0]); $j++)
	{
		$res += pow($argv[0][$j] - $argv[1][$j], 2);
	}
	
	return sqrt($res);
}

var_dump(distance(array(1, 1), array(4, 5)));