php - preg_match() 期望参数是给定的长字符串

Question

我正在检查信用卡字段以确保它们每个都包含四位数字。

function creditcard ($creditCard1,$creditCard2,$creditCard3,$creditCard4)
{
    $regexp="/^[0-9]{4}$/";

    if (preg_match($regexp,$creditCard1,$creditCard2,$creditCard3,$creditCard4))//line 18
    {
        return TRUE;
    }
    else
    {
        echo'<script type="text/javascript">alert("Enter a valid credit card number.")</script>';
        return FALSE;
    }
}

    $creditCard1=$_POST['creditCard1'];
    $creditCard2=$_POST['creditCard2'];
    $creditCard3=$_POST['creditCard3'];
    $creditCard4=$_POST['creditCard4'];
    $creditcard=creditcard($creditCard1,$creditCard2,$creditCard3,$creditCard4);

我遇到了这个错误。

Warning: preg_match() expects parameter 4 to be long, string given in C:\xampp\htdocs\SFASC2\aa.php on line 18

我不知道我做错了什么，谢谢。有很多这样的问题，但没有一个能给我解决方案……而且我一直在用头撞墙，无疑忽略了显而易见的问题。

Answer 1

preg_match一次只检查一个主题。

试试下面的代码:

function creditcard($nums)
{
    $regexp="/^[0-9]{4}$/";

    for ($i = 0; $i < 4; $i++)
        if (! preg_match($regexp, $nums[$i]))
            return FALSE;
    return TRUE;
}

$creditCard1 = $_POST['creditCard1'];
$creditCard2 = $_POST['creditCard2'];
$creditCard3 = $_POST['creditCard3'];
$creditCard4 = $_POST['creditCard4'];

$ok = creditcard([$creditCard1, $creditCard2, $creditCard3, $creditCard4]);
if (! $ok)
    echo '<script type="text/javascript">alert("Enter a valid credit card number.")</script>';