pathinfo()

(PHP 4 >= 4.0.3, PHP 5, PHP 7)

返回文件路径的信息

说明

pathinfo()返回一个关联数组包含有path的信息。返回关联数组还是字符串取决于$options。

参数

要解析的路径。

如果指定了，将会返回指定元素；它们包括：PATHINFO_DIRNAME，PATHINFO_BASENAME和PATHINFO_EXTENSION或PATHINFO_FILENAME。

如果没有指定$options默认是返回全部的单元。

返回值

如果没有传入$options，将会返回包括以下单元的数组array：dirname，basename和extension（如果有），以及filename。

If the$pathdoes not have an extension,noextensionelement will be returned（以下第二个案例）。

If$optionsis present, returns astringcontaining the requested element.

更新日志

范例

Example #1pathinfo()例子

以上例程会输出：

/www/htdocs/inc
lib.inc.php
php
lib.inc

Example #2pathinfo()example showing difference between null and no extension

以上例程的输出类似于：

string(0) ""
Notice: Undefined index: extension in test.php on line 6
NULL

注释

有关取得当前路径信息的说明，请阅读预定义变量一节。Note:

pathinfo()is locale aware, so for it to parse a path containing multibyte characters correctly, the matching locale must be set using thesetlocale()function.

参见

• dirname() 返回路径中的目录部分
• basename() 返回路径中的文件名部分
• parse_url() 解析 URL，返回其组成部分
• realpath() 返回规范化的绝对路径名

Simple example of pathinfo and array destructuring in PHP 7: 

Note:
pathinfo() is locale aware, so for it to parse a path containing multibyte characters correctly, the matching locale must be set using the setlocale() function. 
Reality:
var_dump(pathinfo('中国人2016.xls'));
exit();
array(4) { 'dirname' => string(1) "." 'basename' => string(8) "2016.xls" 'extension' => string(3) "xls" 'filename' => string(4) "2016" } 
Expect(Solve):
setlocale(LC_ALL, 'zh_CN.UTF-8');
var_dump(pathinfo('中国人2016.xls'));
exit();
array(4) { 'dirname' => string(1) "." 'basename' => string(17) "中国人2016.xls" 'extension' => string(3) "xls" 'filename' => string(13) "中国人2016" }

Use this function in place of pathinfo to make it work with UTF-8 encoded file names too 

Checked with version 5.5.12:
It works fine with filenames with utf-8 characters, pathinfo will strip them away:

.. will display:
Array
(
  [dirname] => /mnt/files
  [basename] => 飛兒樂團光茫.mp3
  [extension] => mp3
  [filename] => 飛兒樂團光茫
)

//pathinfo function example

//output
/*
Array
(
  [dirname] => /home/ramki
  [basename] => ramki.pdf
  [extension] => pdf
  [filename] => ramki
)
/home/ramki
ramki.pdf
pdf
ramki
*/

If a file has more than one 'file extension' (seperated by periods), the last one will be returned.
For example:

will produce:
Extension: gz
and not tar.gz

at example from "qutechie at gmail dot com" you can only replace function 'strpos' with 'strrpos'. (strrpos — Find position of last occurrence of a char in a string)
It's simple. For example:

Output will be:
Array
(
  [dirname] => /www/htdocs
  [basename] => index.html
  [extension] => html
  [filename] => index
)

Here is a simple function that gets the extension of a file. Simply using PATHINFO_EXTENSION will yield incorrect results if the path contains a query string with dots in the parameter names (for eg. &x.1=2&y.1=5), so this function eliminates the query string first and subsequently runs PATHINFO_EXTENSION on the clean path/url. 

Note that in PHP 4 (if you're stuck using it), pathinfo only provides dirname, basename, and extension, but not filename. This function will not split a file's stem and extension for you.

If you have filename with utf-8 characters, pathinfo will strip them away:
print_r(pathinfo("/mnt/files/飛兒樂團光茫.mp3"));
 .. will display:
Array
(
  [dirname] => /mnt/files
  [basename] => .mp3
  [extension] => mp3
  [filename] => 
)

about the path, there are one thing you should note : 
On Windows, both slash (/) and backslash (\) are used as directory separator character. In other environments, it is the forward slash (/). (this explain is from basename() function part https://www.php.net/manual/en/function.basename.php)
example: 

Here is an enhanced version of pathinfo() that interprets multi-part extensions like tar.gz as one file extension: 

A warning: this function varies depending on the platform it is being run on. For example, pathinfo('C:\Program Files\Adobe\Reader 9.0\Reader\AcroRd32.exe') will return a different result when run through a winOS PHP platform (local development) vs. a server's UNIX-based OS. A bit like the Locale settings, but unexpected.

It's worth nothing that pathinfo returns foo/index.php for the directory when dealing with URLs like foo/index.php/bar

Note: dirname will be "." (meaning current directory) if the path is just a file name. (PHP 5.4.34) 

Sometimes, it's interessant to get the basename without extension.
So, I appended a new entry 'basenameWE' (Basename Without Extension) to the returned array.

Out :
Array
(
  [dirname] => /var/www/html
  [basename] => example.html
  [extension] => html
  [basenameWE] => example
)

This function is not perfect, but you can use it to convert a relative path to a URL.
Please email me if you can make any improvements. 

For a good example of how platform independent this function is have a look at the different return values that Lostindream and I experienced. Mine is above and Lostindream's is below:
Array
(
  [dirname] => /www/psychicblast/images/1
  [basename] => my three girlfriends.jpg
  [extension] => jpg
)
Array
(
  [dirname] => /www/htdocs
  [basename] => index.html
  [extension] => html
  [filename] => index
)
z

Note that pathinfo($somePath, PATHINFO_EXTENSION) will return '' (empty string) for both of these paths:
- some_random_file
- another_strange_file_ending_in_dot.
That's good, but then note that pathinfo($somePath, PATHINFO_FILENAME) won't end in the dot for 'another_strange_file_ending_in_dot.' - you'll need pathinfo($somePath, PATHINFO_BASENAME) to get the original filename ending in a dot.
Hope this helps!

PHP equivalent for custom implementations. Will be nearly as fast or faster (with long paths): 

Further to my previous post.
This affects servers that run PHP as a cgi module
If you have your own server:
You can use the AcceptPathInfo directive to force the core handler to accept requests with PATH_INFO and thereby restore the ability to use PATH_INFO in server-side includes.
Further information:
http://httpd.apache.org/docs-2.0/mod/core.html#acceptpathinfo

qutechie at gmail dot com wrote a fix for support for filename in PHP 4; however it gets it wrong whenever you have a filename with a . in it (so foo.bar.jpg would return foo instead of foo.bar).
A fix would be:

The idea is that you reverse the string and create a substring that starts after the first '.' and then reverse the result.

Quick fix for lack of support for 'filename' in php4 

Lightweight way to get extension for *nix systems

this will return NULL for dotfiles (hidden files)
Testing:

results:
string(3) "foo"
string(3) "bar"
string(0) ""
NULL
NULL
if you want to get all extensions (substring of file name after first dot) use another expression: 

鹏仔微信 15129739599 鹏仔QQ344225443 鹏仔前端 pjxi.com 共享博客 sharedbk.com