php求数组差集的自定义函数(效率优于array_diff函数)

php求数组差集，代码如下：

 $val) {
if (isset($array_2[$val])) {
unset($array_1[$key]);
}
}

return $array_1;
}

function runtime($mode = 0) {
static $t;

if (!$mode) {
$t = microtime();
return;
}

$t1 = microtime();
list($m0, $s0) = explode(" ", $t);
list($m1, $s1) = explode(" ", $t1);

return sprintf("%.3f", ($s1 + $m1 - $s0 - $m0) * 1000);
}

$array_1 = array();
$array_2 = array();

for ($i = 0; $i <= 5000; $i++) {
$array_1[$i] = mt_rand(0, 100);
$array_2[$i] = mt_rand(0, 100);
}

runtime(); //计时开始
$arr_diff = array_diff($array_1, $array_2);
echo runtime(1); //计时结束并