有时候我们常需要生成一些固定长度的随机字符串，比如uuid，随机字符串等
生成36位uuid
function uuid($prefix = '') {
$chars = md5(uniqid(mt_rand(), true));
$uuid = substr($chars,0,8) . '-';
$uuid .= substr($chars,8,4) . '-';
$uuid .= substr($chars,12,4) . '-';
$uuid .= substr($chars,16,4) . '-';
$uuid .= substr($chars,20,12);
return $prefix . $uuid;
}
echo uuid();
生成随机32位字符串
function str_rand($length = 32, $char = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ') {
if(!is_int($length) || $length < 0) {
return false;
}
$string = '';
for($i = $length; $i > 0; $i--) {
$string .= $char[mt_rand(0, strlen($char) - 1)];
}
return $string;
}
echo str_rand(),
利用微秒时间戳生成32位唯一字符串
$uniqid = md5(uniqid(microtime(true),true));
echo $uniqid;
