问题描述
需要一些帮助,我已经完成了,但无法正常显示或工作。使用 str_replace,假设获取实际的信用卡号并从中删除 -。我有那部分,但是当我创建一个嵌套的 if 语句并使用 is_numeric 进行验证时,它显示“这是一个无效的卡号”;当然如果我把它写成 is_numeric($CreditNumber)) 它也会打印出信用卡号和回声。
另外,我注意到一件事。我将此文件上传到我们的班级服务器,它显示了信用卡号,但它显示了两次,而当我使用 XAMPP 时,它根本不显示。
有什么指点吗?这是代码
<?php
$CreditCard = array ("","8910-1234-5678-6543","OOOO-9123-4567-0123");
foreach ($CreditCard as $CreditNumber) {
if(empty($CreditNumber)) {
echo "Invalid Card Number <br/>";
} else {
$CreditNumber = str_replace("-","",$CreditCard[1]);
echo $CreditNumber;
echo "<br/>";
if (is_numeric()) {
echo "This is an invalid Card Number";
} else {
echo $CreditNumber; //This shows the credit card number without the dashes
}
}
}
?>
编辑:
我已经完成了,它在最后显示了正确的数字,但出于某种奇怪的原因,它与 16 位数字相呼应了两次
<?php
$CreditCard = array ("",$CreditCard[1]);
//echo $CreditNumber;
//echo "<br/>";
if (is_numeric($CreditCard)) {
echo "This is an invalid Card Number";
} else {
echo $CreditNumber; //This shows the credit card number without the dashes
}
}
}
?>
解决方法
正则表达式在这里很有用:
$CreditCard = array("","8910-1234-5678-6543","OOOO-9123-4567-0123");
foreach ($CreditCard as $CreditNumber) {
if (preg_match("/^\d{4}-\d{4}-\d{4}-\d{4}$/",$CreditNumber)) {
echo "VALID: " . $CreditNumber . "\n";
}
else {
echo "INVALID: " . $CreditNumber . "\n";
}
}
打印:
INVALID:
VALID: 8910-1234-5678-6543
INVALID: OOOO-9123-4567-0123
请注意,如果您希望正则表达式模式验证特定供应商卡(例如 Amex、Mastercard、Visa 等),请使用参考 such as this one。
,在您的循环中,您覆盖了 $CreditCard
,因此您无法在之后显示原始格式。您可以使用一个简短的函数在作用域块中进行测试:
function isCreditNumber($creditNumber) {
if (empty($creditNumber)) {
return false;
}
$num = str_replace("-","",$creditNumber);
if (! is_numeric($num)) {
return false;
}
return true;
}
$CreditCard = ["","OOOO-9123-4567-0123"];
foreach ($CreditCard as $CreditNumber) {
if (! isCreditNumber($CreditNumber)) {
echo "Invalid Card Number <br/>";
}
else {
echo $CreditNumber . " is valid<br>";
}
}
输出:
Invalid Card Number
8910-1234-5678-6543 is valid
Invalid Card Number