Implementing simple user input verification using while loop statements in PHP

Title: Using PHP while loop to implement simple user input verification

In PHP programming, user input verification is a very important part, which can ensure the security of the program. sex and stability. The while loop statement can be used to verify user input, and the user can be repeatedly asked until the input meets the requirements. Next we will introduce how to use the while loop in PHP to implement simple user input validation.

First, let’s look at a practical example: Suppose we require the user to enter a legal email address. If the user enters an incorrect email address, the user is required to re-enter it until the user enters it correctly.

The following is a code example that uses PHP's while loop to implement user input verification:

<?php
$isValid = false;

while (!$isValid) {
    $email = readline("请输入您的邮箱地址：");

    if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
        echo "邮箱地址合法！
";
        $isValid = true;
    } else {
        echo "邮箱地址不合法，请重新输入！
";
    }
}
?>

In the above code, we use a while loop to loop and ask the user to enter their email address, and pass FILTER_VALIDATE_EMAIL Filter to verify whether the entered email address is legal. If the email address entered by the user is invalid, we will display a prompt message and continue the loop until the user enters it correctly.

In this way, using PHP's while loop statement, we can easily verify user input and improve the robustness and user experience of the program.

Hope the above example can help you better understand how to use PHP's while loop to implement simple user input validation. Good luck with your programming!

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