用PHP排序用户输入[关闭]

Question

I'm still a beginner in PHP and I want to know how to sort a user input in PHP. I know this doesn't work but I want to know an easier way of doing it. The input must be an integer separated with a comma. Thanks in advance.

 <?php
          //MUST SORT USER INPUT  
          $user_input=$_POST['sort'];
          sort($user_input);
          echo $user_input . ',' ;       
 ?>
<form method='post' action=''>
<input name='arrange' type='text' id='arrange'/>
<input type='submit' class='btn btn-primary' name='submit' value='Submit' />
</form>

Answer 1

Solution is

<?php
    if(isset($_POST['submit']) {
        $input = explode(',', $_POST['arrange']);
        sort($input);
        echo implode(',', $input);  
    }
?>

<form method="POST">
    <input name='arrange' type='text' id='arrange'/>
    <input type='submit' class='btn btn-primary' name='submit' value='Submit' />
</form>