What are the 5 ways to get file extension in php

Method: 1. Use the explode and array_pop functions; 2. Use the strrchr function; 3. Use the substr and strrpos functions; 4. "pathinfo (file) ['extension']" statement; 5. Use strrev, strchr and strrev functions.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

Use more than five methods to obtain the extension of a file name.

Requirements: dir/upload.image.jpg, find .jpg or jpg,

must use PHP The built-in processing function is used for processing. The method cannot be obviously repeated and can be encapsulated into functions, such as get_ext1($file_name), get_ext2($file_name)

The following is The five methods I summarized by referring to online information are relatively simple. Without further ado, let’s go directly to the code:

Method 1:

<?php
function getExt1($filename)
{
         $arr = explode(&#39;.&#39;,$filename);
         return array_pop($arr);
}
$str="dir/upload.image.jpg";
echo getExt1($str);
?>

Output:

jpg

Method 2:

<?php
function getExt2($filename)
{
         $ext = strrchr($filename,&#39;.&#39;);
         return $ext;
}
$str="dir/upload.image.jpg";
echo getExt2($str);
?>

Output:

.jpg

Method 3:

<?php
function getExt3($filename)
{
         $pos = strrpos($filename, &#39;.&#39;);
         $ext = substr($filename, $pos);
         return $ext;
}
$str="dir/upload.image.jpg";
echo getExt3($str);
?>

Output:

.jpg

Method 4:

<?php
function getExt4($filename)
{
         $arr = pathinfo($filename);
         $ext = $arr[&#39;extension&#39;];
         return $ext;
}
$str="dir/upload.image.jpg";
echo getExt4($str);
?>

Output:

jpg

Method 5:

<?php
function getExt5($filename)
{
         $str = strrev($filename);
         return strrev(strchr($str,&#39;.&#39;,true));
}
$str="dir/upload.image.jpg";
echo getExt5($str);
?>

Output:

jpg

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