PHP counts the number of files in the specified folder

<?php
// Give me a folder , Return the number of all files in this folder 
function ShuLiang($url)// Make a way , Give me a parameter 
{
    $sl=0;// Create a variable , Let him default to 0;
    $arr = glob($url);// Save all the files under this path into an array ;
    foreach ($arr as $v)// Circulation is convenient , Bar array $arr Assign to $v;
    {
        if(is_file($v))// Use a first if Judge whether the file in this folder is a file , It could be a folder ;
        {
            $sl++;// If it's a file , Quantity plus one ;
        }
        else
        {
            $sl+=ShuLiang($v."/*");// If it's a folder , Then call the function itself to get the number of files in this folder , This method is called recursion ;
        }
    }
    return $sl;// When this method is finished , Returns a value $sl, This value is the number of all files in the path ;
}
echo ShuLiang("upload/*");// Use this method to check the number of all files in this path   The file name in the root directory is enough ;
?>