问题描述
我想创建精确的 5 个随机字符串,并且复制的可能性最小.最好的方法是什么?谢谢.
I want to create exact 5 random characters string with least possibility of getting duplicated. What would be the best way to do it? Thanks.
推荐答案
$rand = substr(md5(microtime()),rand(0,26),5);
这可能是我最好的猜测——除非您也在寻找特殊字符:
Would be my best guess--Unless you're looking for special characters, too:
$seed = str_split('abcdefghijklmnopqrstuvwxyz' .'ABCDEFGHIJKLMNOPQRSTUVWXYZ' .'0123456789!@#$%^&*()'); // and any other characters shuffle($seed); // probably optional since array_is randomized; this may be redundant $rand = ''; foreach (array_rand($seed, 5) as $k) $rand .= $seed[$k];
示例
而且,对于基于时钟的一个(因为它是增量的,所以冲突更少):
And, for one based on the clock (fewer collisions since it's incremental):
function incrementalHash($len = 5){ $charset = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; $base = strlen($charset); $result = ''; $now = explode(' ', microtime())[1]; while ($now >= $base){ $i = $now % $base; $result = $charset[$i] . $result; $now /= $base; } return substr($result, -5); }
注意:增量意味着更容易猜测;如果您将其用作盐或验证令牌,请不要使用.WCWyb"的盐(现在)意味着 5 秒后它是WCWyg")