php - 如何检查随机字符生成器的重复结果

Question

我制作了一个随机字符生成器，​​但如何检查结果是否重复？
例如，如果我想要 100000 个结果，如何检查 100000 个结果中的某个结果是否不重复？

for ($i=0; $i<$quantity; $i++){
$a = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);
$b = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);
$c = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);
$d = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);
$code = "$a-$b-$c-$d";
echo $code .'<br>';
}

提前致谢!

Answer 1

也许是这样的？使用 in_array()

$previous = array();

for ($i=0; $i<$quantity; $i++){
    $unique_found = false;
    while(!$unique_found){
        $a = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);
        $b = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);
        $c = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);
        $d = substr(str_shuffle("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 4);

        $code = "$a-$b-$c-$d";

        if(!in_array($code,$previous)){
            $unique_found = true;
            $previous[] = $code;
            echo $code .'<br>';
        }
    }

}