PHP-如何使 str_shuffle 产生不同的值？

Question

PHP-如何使 str_shuffle 产生不同的值？    $randomcode="QWERTYUIOPASDFGHJKLZXCVBNM1234567890qwertyuiopasdfghjklzxcvbnm";$randomcode='NT'.substr(str_shuffle($str),5,8);    echo $randomcode.'<br>';    echo $randomcode.'<br>';结果：NT2ZCI1qdXNT2ZCI1qdX如何产生不同的值？我想将它插入到我的数据库中。$randomcode="QWERTYUIOPASDFGHJKLZXCVBNM1234567890qwertyuiopasdfghjklzxcvbnm";$randomcode=substr(str_shuffle($str),5,8);$stmt = $pdo->prepare("insert into AGEGroup (AGE,hidecode) values (:age,$randomcode)");foreach ($_POST['age'] as $age) {    $stmt->execute([':age'=>$age]);}非常感谢

Answer 1

您应该在循环内生成代码。

//list of possible characters in generated code

$charmap = "QWERTYUIOPASDFGHJKLZXCVBNM1234567890qwertyuiopasdfghjklzxcvbnm";

//note using `:randomcode` instead of the direct variable

$stmt = $pdo->prepare("insert into AGEGroup (AGE) values (:age, :randomcode)");

foreach ($_POST['age'] as $age) {

    

    //create a "random" string that is 8 characters.

    //string will never repeat any characters, and can create duplicates

    $code = 'NT' . substr(str_shuffle($charmap), -8);

    //send variables to query on each loop

    $stmt->execute([':age' => $age, ':randomcode' => $code]);

}

正如我在代码注释中所说，这种方法可能有创建重复代码的倾向。它也不包含任何重复的字母/数字。