In-depth analysis of the usage of constant DIRECTORY_SEPARATOR in php, separator_PHP tutorial

In-depth analysis of the usage of constant DIRECTORY_SEPARATOR in php, separator

The example in this article describes the usage of the constant DIRECTORY_SEPARATOR in php. Share it with everyone for your reference. The details are as follows:

What does DIRECTORY_SEPARATOR mean in php? When is it most reasonable to use DIRECTORY_SEPARATOR? Let me introduce to you the php DIRECTORY_SEPARATOR constant.

We know that DIRECTORY_SEPARATOR is a PHP constant, representing a backslash, because the backslashes of Windows and Linux systems are different. In Windows, both slash (/) and backslash () can be used as directory separators. On Linux, the path separator is "/".

So when should DIRECTORY_SEPARATOR be used to represent backslash in PHP code?
For example, this sentence:

Copy code The code is as follows:

require_once dirname(__FILE__).DIRECTORY_SEPARATOR . './../../../wp-config. php';
require_once dirname(__FILE__).DIRECTORY_SEPARATOR.'inc/options.php';

Why does the first part of these two PHP codes use DIRECTORY_SEPARATOR, but the latter part uses "/"
As we all know, under Windows it is and/, while under LINUX it is /

The program runs normally locally. After uploading it to the server, I found that the image was not displayed. The image link was an absolute path var/, and it contained "But I remember that this path has been processed into a relative path"

Copy code The code is as follows:

$path = dirname(dirname(dirname(__FILE__))).'\';
$search = array( $path, '\');
$replace = array( '', '/');
return str_replace($search,$replace,$this->tempfolder).$this->filename_prefix.$public.'.jpg';

As you can see, the first line of code does not work when used on LINUX "\".

The solution is to use the PHP predefined constant DIRECTORY_SEPARATOR to replace path separators such as '' and '/'. I used to think that since Windows and LINUX both support /, then use /. This is correct. But as can be seen from this example, it is more dangerous when path strings are to be processed, so it is best to use DIRECTORY_SEPARATOR

I hope this article will be helpful to everyone’s PHP programming design.

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