PHP verify whether the username starts with a letter and verify the password example_PHP tutorial

Example of php verifying whether the username starts with a letter and verifying the password

This article describes the method of php verifying whether the username starts with a letter and verifying the password. Share it with everyone for your reference. The details are as follows:

Verify that the username starts with a letter and verify that the password can only be a combination of numbers and letters. Three commonly used verification functions: verify the email address format, verify that the password can only be a combination of numbers and letters, and verify that the username starts with A code starting with a letter, which is used when a user registers or submits a form.

The code is as follows:

function is_email($email)
{
if (preg_match("/[a-za-z0-9]+@[a-za-z0-9]+.[a-z]{2,4}/",$email,$mail))
{
Return true;
}
else
{
Return false;
}
}

/**
* Verify if the username starts with a letter
​*/

function is_user_name($user)
{
if (preg_match("/^[a-za-z]{1}([a-za-z0-9]|[._]){3,19}$/",$user,$username))
{
Return true;
}
else
{
Return false;
}
}

/**
* The verification password can only be a combination of numbers and letters
​*/

function is_psd($psd)
{
if (preg_match("/^(w){4,20}$/",$psd,$password))
{
Return true;
}
else
{
Return false;
}
}

I hope this article will be helpful to everyone’s regular expression learning.

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