Hidden file extension, three ways to get file extension in php

Copy the code The code is as follows:

<?php
//Method 1:
function extend_1($file_name)
{
$retval="";
$pt=strrpos($file_name, ". ");
if ($pt) $retval=substr($file_name, $pt+1, strlen($file_name) - $pt);
return ($retval);
}
//Method 2
function extend_2( $file_name)
{
$extend = pathinfo($file_name);
$extend = strtolower($extend["extension"]);
return $extend;
}
//Method 3
function extend_3($file_name)
{
$extend =explode("." , $file_name);
$va=count($extend)-1;
return $extend[$va];
}
?>

The above introduces the three methods of hiding file extensions and obtaining file extensions in PHP, including the content of hidden file extensions. I hope it will be helpful to friends who are interested in PHP tutorials.