blocks|key|3097254|text|pathinfo()|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3097255|$path_info+=+pathinfo('/foo/bar/baz.bill');

echo+$path_info['extension'];+//+"bill"|code-block|syntax|javascript|3097256|entityMap|0|LINK|mutability|MUTABLE|url|http://uk.php.net/manual/en/function.pathinfo.php^0|0|A|0|A|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

<a href="http://uk.php.net/manual/en/function.pathinfo.php" rel="noreferrer"><code>pathinfo()</code></a>

<pre><code>$path_info = pathinfo('/foo/bar/baz.bill');

echo $path_info['extension']; // "bill"
</code></pre>

blocks|key|805574|text|来自其他脚本语言的人总是认为他们的脚本语言更好，因为他们有一个内置的函数来做这件事，而不是PHP+(我现在正在看Pythonistas+:-))。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|805575|事实上，它确实存在，但很少有人知道。认识一下pathinfo()|offset|length|style|CODE|805576|$ext+=+pathinfo($filename,+PATHINFO_EXTENSION);|code-block|syntax|javascript|805577|这是快速和内置的。pathinfo()可以提供其他信息，比如规范路径，这取决于您传递给它的常量。|805578|请记住，如果您希望能够处理非ASCII字符，则需要首先设置区域设置。例如：|805579|setlocale(LC_ALL,'en_US.UTF-8');|805580|另外，请注意，这并没有考虑到文件内容或mime类型，您只获得了扩展名。但这是你想要的。|805581|最后，请注意，这只适用于文件路径，而不适用于URL资源路径，这在PARSE_URL中有介绍。|805582|尽情享受|805583|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.pathinfo.php^0|0|M|A|M|A|0|0|0|9|A|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|17|8|@$D|18|E|19|F|G]]|9|@$D|1A|E|1B|1|1C]]|A|$]]|$1|H|3|I|5|J|7|1D|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|1E|8|@$D|1F|E|1G|F|G]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1H|8|@]|9|@]|A|$]]|$1|Q|3|R|5|J|7|1I|8|@]|9|@]|A|$K|L]]|$1|S|3|T|5|6|7|1J|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1K|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1L|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1M|8|@]|9|@]|A|$]]]|Z|$10|$5|11|12|13|A|$14|15]]]]

People from other scripting languages always think theirs is better because they have a built-in function to do that and not PHP (I am looking at Pythonistas right now :-)).

In fact, it does exist, but few people know it. Meet <a href="http://php.net/manual/en/function.pathinfo.php" rel="noreferrer"><code>pathinfo()</code></a>:

<pre><code>$ext = pathinfo($filename, PATHINFO_EXTENSION);
</code></pre>

This is fast and built-in. <code>pathinfo()</code> can give you other information, such as canonical path, depending on the constant you pass to it.

Remember that if you want to be able to deal with non ASCII characters, you need to set the locale first. E.G:

<pre><code>setlocale(LC_ALL,'en_US.UTF-8');
</code></pre>

Also, note this doesn't take into consideration the file content or mime-type, you only get the extension. But it's what you asked for.

Lastly, note that this works only for a file path, not a URL resources path, which is covered using PARSE_URL.

Enjoy

blocks|key|5353112|text|E-satis的响应是确定文件扩展名的正确方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5353113|或者，您可以使用fileinfo来确定文件的MIME类型，而不是依赖于文件扩展名。|offset|length|5353114|以下是处理用户上传的图片的简化示例：|5353115|//+Code+assumes+necessary+extensions+are+installed+and+a+successful+file+upload+has+already+occurred

//+Create+a+FileInfo+object
$finfo+=+new+FileInfo(null,+'/path/to/magic/file');

//+Determine+the+MIME+type+of+the+uploaded+file
switch+($finfo->file($_FILES['image']['tmp_name'],+FILEINFO_MIME))+{++++++++
++++case+'image/jpg':
++++++++$im+=+imagecreatefromjpeg($_FILES['image']['tmp_name']);
++++break;

++++case+'image/png':
++++++++$im+=+imagecreatefrompng($_FILES['image']['tmp_name']);
++++break;

++++case+'image/gif':
++++++++$im+=+imagecreatefromgif($_FILES['image']['tmp_name']);
++++break;
}|code-block|syntax|javascript|5353116|entityMap|0|LINK|mutability|MUTABLE|url|http://us2.php.net/fileinfo^0|0|8|8|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

E-satis's response is the correct way to determine the file extension.

Alternatively, instead of relying on a files extension, you could use the <a href="http://us2.php.net/fileinfo" rel="nofollow noreferrer">fileinfo</a> to determine the files MIME type.

Here's a simplified example of processing an image uploaded by a user:

<pre><code>// Code assumes necessary extensions are installed and a successful file upload has already occurred

// Create a FileInfo object
$finfo = new FileInfo(null, '/path/to/magic/file');

// Determine the MIME type of the uploaded file
switch ($finfo-&gt;file($_FILES['image']['tmp_name'], FILEINFO_MIME)) { 
 case 'image/jpg':
 $im = imagecreatefromjpeg($_FILES['image']['tmp_name']);
 break;

 case 'image/png':
 $im = imagecreatefrompng($_FILES['image']['tmp_name']);
 break;

 case 'image/gif':
 $im = imagecreatefromgif($_FILES['image']['tmp_name']);
 break;
}
</code></pre>

blocks|key|3097418|text|只要它不包含路径，您也可以使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3097419|array_pop(explode('.',+$fname))|code-block|syntax|javascript|3097420|其中，$fname是文件的名称，例如：my_picture.jpg。结果将是：jpg|offset|length|style|CODE|3097421|entityMap^0|0|0|3|6|J|E|13|3|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|N|$]]

As long as it does not contain a path you can also use:

<pre><code>array_pop(explode('.', $fname))
</code></pre>

Where <code>$fname</code> is a name of the file, for example: <code>my_picture.jpg</code>.
And the outcome would be: <code>jpg</code>

blocks|key|5353160|text|还有SplFileInfo|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5353161|$file+=+new+SplFileInfo($path);
$ext++=+$file->getExtension();|code-block|syntax|javascript|5353162|通常，如果您传递这样的对象而不是字符串，您可以编写更好的代码。那么你的代码就更能说明问题了。从PHP+5.4开始，这是一行代码：|5353163|$ext++=+(new+SplFileInfo($path))->getExtension();|5353164|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/SplFileInfo^0|2|B|2|B|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|F|3|G|5|H|7|12|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|13|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|14|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

There is also <a href="http://php.net/SplFileInfo" rel="noreferrer"><code>SplFileInfo</code></a>:

<pre><code>$file = new SplFileInfo($path);
$ext = $file-&gt;getExtension();
</code></pre>

Often you can write better code if you pass such an object around instead of a string. Your code is more speaking then. Since PHP 5.4 this is a one-liner:

<pre><code>$ext = (new SplFileInfo($path))-&gt;getExtension();
</code></pre>

blocks|key|805657|text|有时不使用pathinfo($path,+PATHINFO_EXTENSION)是很有用的。例如：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|805658|$path+=+'/path/to/file.tar.gz';

echo+ltrim(strstr($path,+'.'),+'.');+//+tar.gz
echo+pathinfo($path,+PATHINFO_EXTENSION);+//+gz|code-block|syntax|javascript|805659|还要注意，pathinfo无法处理某些非ASCII码字符(通常它只是在输出中取消它们)。在扩展中，这通常不是问题，但意识到这一点并不会有什么坏处。|805660|entityMap^0|5|Z|0|0|5|8|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

Sometimes it's useful to not to use <code>pathinfo($path, PATHINFO_EXTENSION)</code>. For example:

<pre><code>$path = '/path/to/file.tar.gz';

echo ltrim(strstr($path, '.'), '.'); // tar.gz
echo pathinfo($path, PATHINFO_EXTENSION); // gz
</code></pre>

Also note that <code>pathinfo</code> fails to handle some non-ASCII characters (usually it just suppresses them from the output). In extensions that usually isn't a problem, but it doesn't hurt to be aware of that caveat.

blocks|key|3097480|text|使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3097481|str_replace('.',+'',+strrchr($file_name,+'.'))|code-block|syntax|javascript|3097482|用于快速扩展名检索(如果您确定您的文件名有扩展名)。|3097483|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Use 

<pre><code>str_replace('.', '', strrchr($file_name, '.'))
</code></pre>

for a quick extension retrieval (if you know for sure your file name has one).

blocks|key|3097529|text|substr($path,+strrpos($path,+'.')+%2B+1);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3097530|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>substr($path, strrpos($path, '.') + 1);
</code></pre>

blocks|key|3097583|text|1)如果您使用的是(PHP+5+>=+5.3.6)，则可以使用+-获取文件扩展名|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3097584|示例代码|3097585|<?php

$info+=+new+SplFileInfo('test.png');
var_dump($info->getExtension());

$info+=+new+SplFileInfo('test.tar.gz');
var_dump($info->getExtension());

?>|code-block|syntax|javascript|3097586|这将输出|3097587|string(3)+"png"
string(2)+"gz"|3097588|2)如果您使用的是(PHP4+>=+4.0.3，PHP5)，则使用另一种获取扩展的方法为|3097589|3097590|<?php

$ext+=+pathinfo('test.png',+PATHINFO_EXTENSION);
var_dump($ext);

$ext+=+pathinfo('test.tar.gz',+PATHINFO_EXTENSION);
var_dump($ext);

?>|3097591|3097592|string(3)+"png"
string(2)+"gz"|3097593|//+EDIT:删除了一个括号|3097594|entityMap^0|0|2|9|G|W|8|0|0|0|0|0|0|18|0|0|4|0|0|0|4|0|0|0|F|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|19|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|1A|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1B|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|1C|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1D|8|@$9|1E|A|1F|B|C]]|D|@]|E|$]]|$1|S|3|G|5|6|7|1G|8|@$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|T|3|U|5|J|7|1J|8|@]|D|@]|E|$K|L]]|$1|V|3|N|5|6|7|1K|8|@$9|1L|A|1M|B|C]]|D|@]|E|$]]|$1|W|3|X|5|J|7|1N|8|@]|D|@]|E|$K|L]]|$1|Y|3|Z|5|6|7|1O|8|@$9|1P|A|1Q|B|C]]|D|@]|E|$]]|$1|10|3|-4|5|6|7|1R|8|@]|D|@]|E|$]]]|11|$]]

1) If you are using (PHP 5 >= 5.3.6)
you can use <a href="http://php.net/manual/en/splfileinfo.getextension.php">SplFileInfo::getExtension</a> — Gets the file extension

Example code

<pre><code>&lt;?php

$info = new SplFileInfo('test.png');
var_dump($info-&gt;getExtension());

$info = new SplFileInfo('test.tar.gz');
var_dump($info-&gt;getExtension());

?&gt;
</code></pre>

This will output

<pre><code>string(3) "png"
string(2) "gz"
</code></pre>

2) Another way of getting the extension if you are using (PHP 4 >= 4.0.3, PHP 5) is <a href="http://php.net/manual/en/function.pathinfo.php">pathinfo</a>

Example code

<pre><code>&lt;?php

$ext = pathinfo('test.png', PATHINFO_EXTENSION);
var_dump($ext);

$ext = pathinfo('test.tar.gz', PATHINFO_EXTENSION);
var_dump($ext);

?&gt;
</code></pre>

This will output

<pre><code>string(3) "png"
string(2) "gz"
</code></pre>

// EDIT: removed a bracket

blocks|key|5353338|text|这将会起作用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5353339|$ext+=+pathinfo($filename,+PATHINFO_EXTENSION);|code-block|syntax|javascript|5353340|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This will work

<pre><code>$ext = pathinfo($filename, PATHINFO_EXTENSION);
</code></pre>

blocks|key|801630|text|我发现pathinfo()和SplFileInfo解决方案对于本地文件系统上的标准文件工作得很好，但是如果你在处理远程文件，你可能会遇到困难，因为有效图像的URL可能在URL的末尾有一个#+(片段标识符)和/或?+(查询参数)，这两种解决方案都会(不正确地)将其视为文件扩展名的一部分。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|801631|我发现这是一种在网址上使用pathinfo()的可靠方法，首先对其进行解析，以剔除文件扩展名后面不必要的杂乱内容：|801632|$url_components+=+parse_url($url);+//+First+parse+the+URL
$url_path+=+$url_components['path'];+//+Then+get+the+path+component
$ext+=+pathinfo($url_path,+PATHINFO_EXTENSION);+//+Then+use+pathinfo()|code-block|syntax|javascript|801633|entityMap^0|3|A|E|B|2L|1|2X|1|0|D|A|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$]]

I found that the <code>pathinfo()</code> and <code>SplFileInfo</code> solutions works well for standard files on the local file system, but you can run into difficulties if you're working with remote files as URLs for valid images may have a <code>#</code> (fragment identifiers) and/or <code>?</code> (query parameters) at the end of the URL, which both those solutions will (incorrect) treat as part of the file extension.

I found this was a reliable way to use <code>pathinfo()</code> on a URL after first parsing it to strip out the unnecessary clutter after the file extension:

<pre><code>$url_components = parse_url($url); // First parse the URL
$url_path = $url_components['path']; // Then get the path component
$ext = pathinfo($url_path, PATHINFO_EXTENSION); // Then use pathinfo()
</code></pre>

blocks|key|801660|text|下面是一个例子。假设$filename为"example.txt"，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|801661|$ext+=+substr($filename,+strrpos($filename,+'.',+-1),+strlen($filename));|code-block|syntax|javascript|801662|所以$ext将是".txt“。|801663|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Here is an example. Suppose $filename is "example.txt",

<pre><code>$ext = substr($filename, strrpos($filename, '.', -1), strlen($filename));
</code></pre>

So $ext will be ".txt".

blocks|key|805819|text|在PHP中获取文件扩展名的最简单方法是使用PHP的内置函数pathinfo。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|805820|$file_ext+=+pathinfo('your_file_name_here',+PATHINFO_EXTENSION);
echo+($file_ext);+//+The+output+should+be+the+extension+of+the+file+e.g.,+png,+gif,+or+html|code-block|syntax|javascript|805821|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.pathinfo.php^0|T|8|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

The simplest way to get file extension in PHP is to use PHP's built-in function <a href="http://php.net/manual/en/function.pathinfo.php" rel="nofollow noreferrer">pathinfo</a>.

<pre><code>$file_ext = pathinfo('your_file_name_here', PATHINFO_EXTENSION);
echo ($file_ext); // The output should be the extension of the file e.g., png, gif, or html
</code></pre>

blocks|key|5353625|text|一个简单的解决方法就是这样。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5353626|//+Exploding+the+file+based+on+the+.+operator
$file_ext+=+explode('.',+$filename);

//+Count+taken+(if+more+than+one+.+exist;+files+like+abc.fff.2013.pdf
$file_ext_count+=+count($file_ext);

//+Minus+1+to+make+the+offset+correct
$cnt+=+$file_ext_count+-+1;

//+The+variable+will+have+a+value+pdf+as+per+the+sample+file+name+mentioned+above.
$file_extension+=+$file_ext[$cnt];|code-block|syntax|javascript|5353627|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

A quick fix would be something like this.

<pre><code>// Exploding the file based on the . operator
$file_ext = explode('.', $filename);

// Count taken (if more than one . exist; files like abc.fff.2013.pdf
$file_ext_count = count($file_ext);

// Minus 1 to make the offset correct
$cnt = $file_ext_count - 1;

// The variable will have a value pdf as per the sample file name mentioned above.
$file_extension = $file_ext[$cnt];
</code></pre>

blocks|key|801733|text|示例网址：http://example.com/myfolder/sympony.mp3?a=1&b=2#XYZ|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|801734|A)不要使用建议的不安全|801735|pathinfo($url)['dirname']++++'http://example.com/myfolder'
pathinfo($url)['basename']+++'sympony.mp3?a=1&b=2#XYZ'+++++++++//+<-------+BAD+!!
pathinfo($url)['extension']++'mp3?a=1&b=2#XYZ'+++++++++++++++++//+<-------+BAD+!!
pathinfo($url)['filename']+++'sympony'|code-block|syntax|javascript|801736|B)使用PARSE_URL|801737|parse_url($url)['scheme']++++'http'
parse_url($url)['host']++++++'example.com'
parse_url($url)['path']++++++'/myfolder/sympony.mp3'
parse_url($url)['query']+++++'aa=1&bb=2'
parse_url($url)['fragment']++'XYZ'|801738|奖励:查看all+native+PHP+examples|801739|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.parse-url.php#refsect1-function.parse-url-examples|1|https://stackoverflow.com/questions/6768793/get-the-full-url-in-php/26944636#26944636^0|5|1F|5|1F|0|0|0|4|9|0|0|0|5|N|1|0^^$0|@$1|2|3|4|5|6|7|13|8|@$9|14|A|15|B|C]|$9|16|A|17|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|18|8|@]|E|@]|F|$]]|$1|I|3|J|5|K|7|19|8|@]|E|@]|F|$L|M]]|$1|N|3|O|5|6|7|1A|8|@]|E|@$9|1B|A|1C|1|1D]]|F|$]]|$1|P|3|Q|5|K|7|1E|8|@]|E|@]|F|$L|M]]|$1|R|3|S|5|6|7|1F|8|@]|E|@$9|1G|A|1H|1|1I]]|F|$]]|$1|T|3|-4|5|6|7|1J|8|@]|E|@]|F|$]]]|U|$V|$5|W|X|Y|F|$Z|10]]|11|$5|W|X|Y|F|$Z|12]]]]

Example URL: <code>http://example.com/myfolder/sympony.mp3?a=1&amp;b=2#XYZ</code>
A) Don't use suggested unsafe <a href="http://php.net/manual/en/function.pathinfo.php#example-2610" rel="noreferrer"><code>PATHINFO</code></a>:
<pre><code>pathinfo($url)['dirname'] 'http://example.com/myfolder'
pathinfo($url)['basename'] 'sympony.mp3?a=1&amp;b=2#XYZ' // &lt;------- BAD !!
pathinfo($url)['extension'] 'mp3?a=1&amp;b=2#XYZ' // &lt;------- BAD !!
pathinfo($url)['filename'] 'sympony'
</code></pre>
B) Use <a href="http://php.net/manual/en/function.parse-url.php#refsect1-function.parse-url-examples" rel="noreferrer">PARSE_URL</a>:
<pre><code>parse_url($url)['scheme'] 'http'
parse_url($url)['host'] 'example.com'
parse_url($url)['path'] '/myfolder/sympony.mp3'
parse_url($url)['query'] 'aa=1&amp;bb=2'
parse_url($url)['fragment'] 'XYZ'
</code></pre>
BONUS: View <a href="https://stackoverflow.com/questions/6768793/get-the-full-url-in-php/26944636#26944636">all native PHP examples</a>

blocks|key|3943813|text|您可以获取特定文件夹中的所有文件扩展名，并使用特定的文件扩展名执行操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3943814|<?php
++++$files+=+glob("abc/*.*");+//+abc+is+the+folder+all+files+inside+folder
++++//print_r($files);
++++//echo+count($files);
++++for($i=0;+$i<count($files);+$i%2B%2B):
+++++++++$extension+=+pathinfo($files[$i],+PATHINFO_EXTENSION);
+++++++++$ext[]+=+$extension;
+++++++++//+Do+operation+for+particular+extension+type
+++++++++if($extension=='html'){
+++++++++++++//+Do+operation
+++++++++}
++++endfor;
++++print_r($ext);
?>|code-block|syntax|javascript|3943815|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can get all file extensions in a particular folder and do operations with a specific file extension:

<pre><code>&lt;?php
 $files = glob("abc/*.*"); // abc is the folder all files inside folder
 //print_r($files);
 //echo count($files);
 for($i=0; $i&lt;count($files); $i++):
 $extension = pathinfo($files[$i], PATHINFO_EXTENSION);
 $ext[] = $extension;
 // Do operation for particular extension type
 if($extension=='html'){
 // Do operation
 }
 endfor;
 print_r($ext);
?&gt;
</code></pre>

blocks|key|3943849|text|您还可以尝试执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3943850|+pathinfo(basename($_FILES["fileToUpload"]["name"]),+PATHINFO_EXTENSION)|code-block|syntax|javascript|3943851|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can try also this:

<pre><code> pathinfo(basename($_FILES["fileToUpload"]["name"]), PATHINFO_EXTENSION)
</code></pre>

blocks|key|801856|text|pathinfo是一个数组。我们可以检查目录名、文件名、扩展名等：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|801857|$path_parts+=+pathinfo('test.png');

echo+$path_parts['extension'],+"\n";
echo+$path_parts['dirname'],+"\n";
echo+$path_parts['basename'],+"\n";
echo+$path_parts['filename'],+"\n";|code-block|syntax|javascript|801858|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.pathinfo.php^0|K|B|0|8|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

<a href="http://php.net/manual/en/function.pathinfo.php" rel="nofollow noreferrer">pathinfo</a> is an array. We can check directory name, file name, extension, etc.:

<pre><code>$path_parts = pathinfo('test.png');

echo $path_parts['extension'], "\n";
echo $path_parts['dirname'], "\n";
echo $path_parts['basename'], "\n";
echo $path_parts['filename'], "\n";
</code></pre>

blocks|key|801872|text|如果您正在寻找速度(例如在路由器中)，您可能不希望将所有东西都标记化。使用/root/my.folder/my.css时，许多其他答案都会失败|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|801873|ltrim(strrchr($PATH,+'.'),'.');|code-block|syntax|javascript|801874|entityMap^0|11|M|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

If you are looking for speed (such as in a router), you probably don't want to tokenize everything. Many other answers will fail with <code>/root/my.folder/my.css</code> 

<pre><code>ltrim(strrchr($PATH, '.'),'.');
</code></pre>

blocks|key|3098141|text|使用substr($path,+strrpos($path,'.')%2B1);。这是所有比较中最快的方法。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3098142|@Kurt+Zhong已经回复了。|3098143|让我们在这里检查比较结果：https://eval.in/661574|3098144|entityMap|0|LINK|mutability|MUTABLE|url|https://eval.in/661574^0|2|10|0|0|D|M|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|V|8|@]|D|@$9|W|A|X|1|Y]]|E|$]]|$1|J|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|Q]]]]

Use <code>substr($path, strrpos($path,'.')+1);</code>. It is the fastest method of all compares.

@Kurt Zhong already answered.

Let's check the comparative result here: <a href="https://eval.in/661574" rel="nofollow noreferrer">https://eval.in/661574</a>

blocks|key|5353987|text|你也可以试试这个(它适用于PHP5.*和7)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5353988|$info+=+new+SplFileInfo('test.zip');
echo+$info->getExtension();+//+-----+Output+----->+zip|code-block|syntax|javascript|5353989|提示:如果文件没有扩展名，则返回空字符串|5353990|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can try also this (it works on PHP 5.* and 7):

<pre><code>$info = new SplFileInfo('test.zip');
echo $info-&gt;getExtension(); // ----- Output -----&gt; zip
</code></pre>

Tip: it returns an empty string if the file doesn't have an extension

blocks|key|3098240|text|尽管“最佳方式”尚有争议，但我认为这是最好的方式，原因如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3098241|function+getExt($path)
{
++++$basename+=+basename($path);
++++return+substr($basename,+strlen(explode('.',+$basename)[0])+%2B+1);
}|code-block|syntax|javascript|3098242|对于一个扩展名，它可以使用多个部分，例如tar.gz|offset|length|style|CODE|3098243|Short++efficient+|unordered-list-item|3098244|ordered-list-item|3098245|它可以使用文件名和完整路径|3098246|3098247|3098248|entityMap^0|0|0|K|6|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Z|8|@$I|10|J|11|K|L]]|9|@]|A|$]]|$1|M|3|N|5|O|7|12|8|@]|9|@]|A|$]]|$1|P|3|-4|5|Q|7|13|8|@]|9|@]|A|$]]|$1|R|3|S|5|Q|7|14|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|15|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|16|8|@]|9|@]|A|$]]|$1|V|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|W|$]]

Although the "best way" is debatable, I believe this is the best way for a few reasons:

<pre><code>function getExt($path)
{
 $basename = basename($path);
 return substr($basename, strlen(explode('.', $basename)[0]) + 1);
}
</code></pre>

<ol>
<li>It works with multiple parts to an extension, eg <code>tar.gz</code></li>
<li>Short and efficient code</li>
<li>It works with both a filename and a complete path</li>
</ol>

blocks|key|806125|text|实际上，我正在找那个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|806126|<?php

$url+=+'http://example.com/myfolder/sympony.mp3?a=1&b=2#XYZ';
$tmp+=+@parse_url($url)['path'];
$ext+=+pathinfo($tmp,+PATHINFO_EXTENSION);

var_dump($ext);|code-block|syntax|javascript|806127|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Actually, I was looking for that.

<pre class="lang-php prettyprint-override"><code>&lt;?php

$url = 'http://example.com/myfolder/sympony.mp3?a=1&amp;b=2#XYZ';
$tmp = @parse_url($url)['path'];
$ext = pathinfo($tmp, PATHINFO_EXTENSION);

var_dump($ext);
</code></pre>

blocks|key|5354099|text|如果你有像name.ext这样的文件名，这是最好的方式(丑陋，但有时也会发生)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5354100|$ext+++++=+explode('.',+$filename);+//+Explode+the+string
$my_ext++=+end($ext);+//+Get+the+last+entry+of+the+array

echo+$my_ext;|code-block|syntax|javascript|5354101|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

IMO, this is the best way if you have filenames like name.name.name.ext (ugly, but it sometimes happens):
<pre><code>$ext = explode('.', $filename); // Explode the string
$my_ext = end($ext); // Get the last entry of the array

echo $my_ext;
</code></pre>

blocks|key|3944256|text|ltrim(strstr($file_url,+'.'),+'.')|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3944257|unstyled|3944258|如果你有像name.ext这样的文件名，这是最好的方法(丑陋，但有时会发生|blockquote|3944259|3944260|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|M|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|N|8|@]|9|@]|A|$]]|$1|I|3|-4|5|E|7|O|8|@]|9|@]|A|$]]|$1|J|3|-4|5|E|7|P|8|@]|9|@]|A|$]]]|K|$]]

<pre><code>ltrim(strstr($file_url, '.'), '.')
</code></pre>

<blockquote>
 this is the best way if you have filenames like name.name.name.ext (ugly, but it sometimes happens
</blockquote>

blocks|key|5354180|text|抱歉..。“简短的问题；但不是简短的回答”|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5354181|路径的示例1|offset|length|style|BOLD|5354182|$path+=+"/home/ali/public_html/wp-content/themes/chicken/css/base.min.css";
$name+=+pathinfo($path,+PATHINFO_FILENAME);
$ext++=+pathinfo($path,+PATHINFO_EXTENSION);
printf('<hr>+Name:+%25s+ +Extension:+%25s',+$name,+$ext);|code-block|syntax|javascript|5354183|URL的示例2|5354184|$url+=+"//www.example.com/dir/file.bak.php?Something%2Bis%2Bwrong=hello";
$url+=+parse_url($url);
$name+=+pathinfo($url['path'],+PATHINFO_FILENAME);
$ext++=+pathinfo($url['path'],+PATHINFO_EXTENSION);
printf('<hr>+Name:+%25s+ +Extension:+%25s',+$name,+$ext);|5354185|示例1的输出：|5354186|Name:+base.min
Extension:+css|5354187|示例2的输出：|5354188|Name:+file.bak
Extension:+php|5354189|参考文献|5354190|5354191|https://www.php.net/manual/en/function.pathinfo.php|ordered-list-item|5354192|https://www.php.net/manual/en/function.realpath.php|5354193|https://www.php.net/manual/en/function.parse-url.php|5354194|5354195|entityMap|0|LINK|mutability|MUTABLE|url|1|2^0|0|3|3|0|0|0|3|4|3|0|0|0|7|0|0|0|7|0|0|0|4|0|0|0|1F|0|1F|0|0|0|1F|0|1F|1|0|0|1G|0|1G|2|0|0^^$0|@$1|2|3|4|5|6|7|1I|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1J|8|@$D|1K|E|1L|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|1M|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|1N|8|@$D|1O|E|1P|F|G]|$D|1Q|E|1R|F|G]]|9|@]|A|$]]|$1|O|3|P|5|J|7|1S|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|1T|8|@$D|1U|E|1V|F|G]]|9|@]|A|$]]|$1|S|3|T|5|J|7|1W|8|@]|9|@]|A|$K|L]]|$1|U|3|V|5|6|7|1X|8|@$D|1Y|E|1Z|F|G]]|9|@]|A|$]]|$1|W|3|X|5|J|7|20|8|@]|9|@]|A|$K|L]]|$1|Y|3|Z|5|6|7|21|8|@$D|22|E|23|F|G]]|9|@]|A|$]]|$1|10|3|-4|5|6|7|24|8|@]|9|@]|A|$]]|$1|11|3|12|5|13|7|25|8|@$D|26|E|27|F|G]]|9|@$D|28|E|29|1|2A]]|A|$]]|$1|14|3|15|5|13|7|2B|8|@$D|2C|E|2D|F|G]]|9|@$D|2E|E|2F|1|2G]]|A|$]]|$1|16|3|17|5|13|7|2H|8|@$D|2I|E|2J|F|G]]|9|@$D|2K|E|2L|1|2M]]|A|$]]|$1|18|3|-4|5|6|7|2N|8|@]|9|@]|A|$]]|$1|19|3|-4|5|6|7|2O|8|@]|9|@]|A|$]]]|1A|$1B|$5|1C|1D|1E|A|$1F|12]]|1G|$5|1C|1D|1E|A|$1F|15]]|1H|$5|1C|1D|1E|A|$1F|17]]]]

<h2>Sorry... "Short Question; But NOT Short Answer"</h2>

Example 1 for PATH

<pre><code>$path = "/home/ali/public_html/wp-content/themes/chicken/css/base.min.css";
$name = pathinfo($path, PATHINFO_FILENAME);
$ext = pathinfo($path, PATHINFO_EXTENSION);
printf('&lt;hr&gt; Name: %s &lt;br&gt; Extension: %s', $name, $ext);
</code></pre>

Example 2 for URL

<pre><code>$url = "//www.example.com/dir/file.bak.php?Something+is+wrong=hello";
$url = parse_url($url);
$name = pathinfo($url['path'], PATHINFO_FILENAME);
$ext = pathinfo($url['path'], PATHINFO_EXTENSION);
printf('&lt;hr&gt; Name: %s &lt;br&gt; Extension: %s', $name, $ext);
</code></pre>

Output of example 1:

<pre><code>Name: base.min
Extension: css
</code></pre>

Output of example 2:

<pre><code>Name: file.bak
Extension: php
</code></pre>

<h2>References</h2>

<ol>
<li><a href="https://www.php.net/manual/en/function.pathinfo.php" rel="noreferrer">https://www.php.net/manual/en/function.pathinfo.php</a></li>
<li><a href="https://www.php.net/manual/en/function.realpath.php" rel="noreferrer">https://www.php.net/manual/en/function.realpath.php</a></li>
<li><a href="https://www.php.net/manual/en/function.parse-url.php" rel="noreferrer">https://www.php.net/manual/en/function.parse-url.php</a></li>
</ol>

blocks|key|3944364|text|$ext+=+preg_replace('/%5E.*\.([%5E.]%2B)$/D',+'$1',+$fileName);|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3944365|preg_replace方法我们使用正则表达式搜索和替换。在preg_replace函数中，第一个参数是搜索的模式，第二个参数$1是对第一个(.*)匹配的任何内容的引用，第三个参数是文件名。|3944366|另一种方法是，我们还可以使用strrpos来查找a‘’最后一次出现的位置。并将该位置递增1，以便从(.)|3944367|$ext+=+substr($fileName,+strrpos($fileName,+'.')+%2B+1);|3944368|entityMap^0|0|1L|0|0|0|0|1I|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Q|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|R|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|L|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|M|$]]

<code>$ext = preg_replace('/^.*\.([^.]+)$/D', '$1', $fileName);</code>

preg_replace approach we using regular expression search and replace. In preg_replace function first parameter is pattern to the search, second parameter $1 is a reference to whatever is matched by the first (.*) and third parameter is file name.

Another way, we can also use strrpos to find the position of the last occurrence of a ‘.’ in a file name and increment that position by 1 so that it will explode string from (.)

<code>$ext = substr($fileName, strrpos($fileName, '.') + 1);</code>

blocks|key|3098524|text|再快点！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3098525|换句话说，请停止使用pathinfo来做这项工作。它相当慢。这样的低级调用需要非常快，所以我认为值得研究一下。我尝试了一些方法(不同的字符串长度，扩展长度，每个方法都有多次运行)，下面是一些合理的方法。我不得不更新之前的统计数据，因为php版本(以及内核和其他很多东西)会发生变化，但在Linux服务器上，结果总是一样的。|3098526|/*+++387+ns+*/+function+method1($s)+{return+preg_replace("/.*\./","",$s);}+//+edge+case+problem
/*+++769+ns+*/+function+method2($s)+{preg_match("/\.([%5E\.]%2B)$/",$s,$a);return+$a[1];}
/*++++67+ns+*/+function+method3($s)+{$n+=+strrpos($s,".");+if($n===false)+return+"";return+substr($s,$n%2B1);}
/*+++175+ns+*/+function+method4($s)+{$a+=+explode(".",$s);$n+=+count($a);+if($n==1)+return+"";return+$a[$n-1];}
/*+++731+ns+*/+function+method5($s)+{return+pathinfo($s,+PATHINFO_EXTENSION);}
/*+++732+ns+*/+function+method6($s)+{return+(new+SplFileInfo($s))->getExtension();}|code-block|syntax|javascript|3098527|测试字符串是"something.that.contains.dots.txt"；如您所见，测量结果被重新划分为纳秒。SplFileInfo和pathinfo都是很棒的家伙，但对于这种工作来说，唤醒他们是不值得的。出于同样的原因，explode()比正则表达式快得多。非常简单的工具几乎总是胜过更复杂的工具。|offset|length|style|CODE|3098528|附注:在Windows上，结果完全不同。如果您使用的是IIS，我想为您自己的案例运行这些数字是值得的。|3098529|结论|3098530|这似乎是武士的方式：|3098531|function+fileExtension($s)+{
++++$n+=+strrpos($s,".");
++++return+($n===false)+?+""+:+substr($s,$n%2B1);
}|3098532|一些测试用例|3098533|File+name++++++++++++fileExtension()
----------------------------------------
file+++++++++++++++++""
file.++++++++++++++++""
file.txt+++++++++++++"txt"
file.txt.bin+++++++++"bin"
file.txt.whatever++++"whatever"
.htaccess++++++++++++"htaccess"|3098534|(最后一个有点特殊；它可以只是一个扩展，也可以是一个纯名称为".htaccess“的空扩展，我不确定是否有这样的规则。因此，只要您知道自己在做什么，我想您可以同时使用这两种方法。)|3098535|entityMap^0|0|0|0|1N|B|1Z|8|37|9|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|17|8|@$K|18|L|19|M|N]|$K|1A|L|1B|M|N]|$K|1C|L|1D|M|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1E|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1F|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1G|8|@]|9|@]|A|$]]|$1|U|3|V|5|F|7|1H|8|@]|9|@]|A|$G|H]]|$1|W|3|X|5|6|7|1I|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|F|7|1J|8|@]|9|@]|A|$G|H]]|$1|10|3|11|5|6|7|1K|8|@]|9|@]|A|$]]|$1|12|3|-4|5|6|7|1L|8|@]|9|@]|A|$]]]|13|$]]

<h2>Do it faster!</h2>
In other words, please stop using pathinfo for this job. It's rather slow. Such low-level calls need to be very fast so I thought it was worth some research.
I tried a few methods (with various string lengths, extension lengths, multiple runs each), here's some reasonable ones. I had to update the previous stats because php versions (and kernels and lots of other things) change, but on Linux servers, the takeaway is always the same.
<pre class="lang-php prettyprint-override"><code>/* 387 ns */ function method1($s) {return preg_replace(&quot;/.*\./&quot;,&quot;&quot;,$s);} // edge case problem
/* 769 ns */ function method2($s) {preg_match(&quot;/\.([^\.]+)$/&quot;,$s,$a);return $a[1];}
/* 67 ns */ function method3($s) {$n = strrpos($s,&quot;.&quot;); if($n===false) return &quot;&quot;;return substr($s,$n+1);}
/* 175 ns */ function method4($s) {$a = explode(&quot;.&quot;,$s);$n = count($a); if($n==1) return &quot;&quot;;return $a[$n-1];}
/* 731 ns */ function method5($s) {return pathinfo($s, PATHINFO_EXTENSION);}
/* 732 ns */ function method6($s) {return (new SplFileInfo($s))-&gt;getExtension();}
</code></pre>
Test string was &quot;something.that.contains.dots.txt&quot;; as you see, measurements were divided back to nanoseconds. <code>SplFileInfo</code> and <code>pathinfo</code> are great fellas, but for this kind of job it's simply not worth it to wake them up. For the same reason, <code>explode()</code> is considerably faster than regex. Very simple tools almost always beat more sophisticated ones.
Side note: on Windows, results are totally different. I guess it's worth to run the numbers for your own case if you're using IIS.
<h2>Conclusion</h2>
This seems to be the Way of the Samurai:
<pre class="lang-php prettyprint-override"><code>function fileExtension($s) {
 $n = strrpos($s,&quot;.&quot;);
 return ($n===false) ? &quot;&quot; : substr($s,$n+1);
}
</code></pre>
<h2>Some test cases</h2>
<pre><code>File name fileExtension()
----------------------------------------
file &quot;&quot;
file. &quot;&quot;
file.txt &quot;txt&quot;
file.txt.bin &quot;bin&quot;
file.txt.whatever &quot;whatever&quot;
.htaccess &quot;htaccess&quot;
</code></pre>
(The last one is a bit special; it could be only an extension, or an empty extension with the pure name being &quot;.htaccess&quot;, I'm not sure if there's a rule for that. So I guess you can go with both, as long as you know what you're doing.)

blocks|key|806265|text|我尝试了一个简单的解决方案，它可能会帮助其他人从具有get参数的URL中获取文件名|type|unstyled|depth|inlineStyleRanges|entityRanges|data|806266|<?php

$path+=+"URL+will+be+here";
echo+basename(parse_url($path)['path']);

?>|code-block|syntax|javascript|806267|谢谢|806268|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I tried one simple solution it might help to someone else to get just filename from the URL which having get parameters
<pre><code>&lt;?php

$path = &quot;URL will be here&quot;;
echo basename(parse_url($path)['path']);

?&gt;
</code></pre>
Thanks

This is a question you can read everywhere on the web with various answers:

<pre><code>$ext = end(explode('.', $filename));
$ext = substr(strrchr($filename, '.'), 1);
$ext = substr($filename, strrpos($filename, '.') + 1);
$ext = preg_replace('/^.*\.([^.]+)$/D', '$1', $filename);

$exts = split("[/\\.]", $filename);
$n = count($exts)-1;
$ext = $exts[$n];
</code></pre>

etc.

However, there is always "the best way" and it should be on Stack Overflow.

How do I get a file extension in PHP?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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这是一个你可以在网络上随处可见的问题，有各种各样的答案：$ext = end(explode('.', $filename));$ext = substr(strrchr($filename, '.'), 1);$ext = substr($filename, strrpos($filename, '.') + 1);...

问如何在PHP中获得文件扩展名？
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问如何在PHP中获得文件扩展名？EN