How to generate random strings in php without repeating them

How to implement php to generate random strings without repetition: first create a PHP sample file; then define a "random_str" method; then use functions such as "array_merge" to generate a string containing uppercase English letters, lowercase English letters An array of letters and numbers will do.

Recommended: "PHP Video Tutorial"

php generates random strings (no duplication)

function random_str($length)
{
//生成一个包含 大写英文字母, 小写英文字母, 数字 的数组
$arr = array_merge(range(0, 9), range('a', 'z'), range('A', 'Z'));
$str = '';
$arr_len = count($arr);
for ($i = 0; $i < $length; $i++)
{
$rand = mt_rand(0, $arr_len-1);
$str.=$arr[$rand];
}
return $str.&#39;<br>&#39;;
}
for($j=0;$j<1200;$j++){
$a= random_str(18);
//$a=substr(md5(date(&#39;YmdHis&#39;).rand(1000,9999)),   8,   16);
//echo $a.&#39;<br><br>&#39;;
}

The above is the detailed content of How to generate random strings in php without repeating them. For more information, please follow other related articles on the PHP Chinese website!