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This time I will bring you a summary of how PHP obtains file extensions. What are the precautions for PHP to obtain file extensions? The following is a practical case, let's take a look.
This is a written test question I encountered when applying for an internship:
Use more than five methods to obtain the extension of a file.
Requirements: dir/upload.image.jpg, find .jpg or jpg,
Must use PHP's own processing function for processing, the method cannot be obviously repeated, and can be encapsulated into a function, For example, get_ext1($file_name)
, get_ext2($file_name)
The following are five methods I summarized by referring to online information. They are all relatively simple and do not say much. Say, go directly to the code:
Method 1:
function getExt1($filename) { $arr = explode('.',$filename); return array_pop($arr);; }
Method 2:
function getExt2($filename) { $ext = strrchr($filename,'.'); return $ext; }
Method 3:
function getExt3($filename) { $pos = strrpos($filename, '.'); $ext = substr($filename, $pos); return $ext; }
Method 4:
function getExt4($filename) { $arr = pathinfo($filename); $ext = $arr['extension']; return $ext; }
Method 5:
function getExt5($filename) { $str = strrev($filename); return strrev(strchr($str,'.',true)); }
I believe you have mastered it after reading the case in this article For more exciting methods, please pay attention to other related articles on the php Chinese website!
Recommended reading:
Detailed explanation of the steps for PHP to use file_get_contents to send http requests
PHP implements random elimination algorithm
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