如何将我的电子邮件验证脚本放入php函数

Struggling to create a function to validate any email address using the script below

if (!preg_match('/^(?=^.{6,64}$)[a-zA-Z0-9][a-zA-Z0-9\._\-&!?=#]*@/', $user_mail)) {
            $error_mail        = empty_mail;
            $display_form      = TRUE;
            $validation_error  = TRUE;
          } else {
            $domain = preg_replace('/^[a-zA-Z0-9][a-zA-Z0-9\._\-&!?=#]*@/', '', $user_mail);
            if (!checkdnsrr($domain)) {
              $error_mail        = empty_mail;
              $display_form      = TRUE;
              $validation_error  = TRUE;
            }
          }

Server-side validation:

It is a good idea to always validate data server-side. Of course you need to do this client site with JavaScript but you can never trust client validation because you can easily pass that.

That said, hereby the simple PHP server-side e-mail address validation:

//Will return a boolean
filter_var('bob@example.com', FILTER_VALIDATE_EMAIL);

Documentation: http://php.net/manual/en/function.filter-var.php

Define the function and call the function with parameters like this

    <?php

    function validate_email($user_mail)
    {

       $pattern = "/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,})$/";

       if (preg_match($pattern, $user_mail)) {

          return "valid email format";
       }
       else
       {
          return "Invalid email format";
       }


    }

    echo validate_email('jothi007@@gmail.com');

    ?>

OUTPUT :

valid email format