What are the three ways to get the file extension in php

Obtaining method: 1. Use the "array_pop(explode('.', file name))" statement; 2. Use the "pathinfo (file name) ['extension']" statement; 3. Use "strrev (strchr(strrev(filename),'.',true))" statement.

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

php gets the file suffix Name 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

Description:

explode() function uses a string split Another string and returns an array of strings.

array_pop() function deletes the last element in the array.

php method 2 to get the file suffix name:

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

Output:

jpg

Description:

pathinfo() function returns information about the file path in the form of an array.

The returned array elements are as follows:

• [dirname]: directory path

• [basename]: file name

• [extension]: File suffix name

• [filename]: File name without suffix

php method 3 to get the file suffix name:

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

Output:

jpg

Description:

strrev() function reverses a string.

strchr() function searches for the first occurrence of a string in another string. Syntax:

strchr(string,search,before_search);

Parameter	Description
string	Required. Specifies the string to be searched for.
search	Required. Specifies the string to search for. If the argument is a number, searches for characters that match the ASCII value for that number.
before_search	Optional. A Boolean value with a default value of "false". If set to "true", it will return the portion of the string preceding the first occurrence of the search parameter.

Return value: Returns the rest of the string (from the matching point). Returns FALSE if the searched string is not found.

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