Performance analysis of is_dir, is_file, file_exists functions in PHP_PHP tutorial

Performance analysis of is_dir, is_file, file_exists functions in PHP. We have summarized the usage of the three functions in specific places from each method. Students in need can refer to it.

Performance analysis of is_dir, is_file, file_exists functions in php
php,is_dir,is_file,file_exists

Obviously file_exists is affected by asp, because asp not only has fileExists but also folderExists and driverExists. So what does file_exists mean in PHP?

PHP’s file_exists = is_dir + is_file

It can determine whether the file exists and whether the directory exists. However, the execution efficiency of such a comprehensive function is very low, just like the request in asp does not specify whether it is a form, get, or cookies, so the conclusion is:

◦If you want to determine whether the directory exists, please use the independent function is_dir(directory)
◦If you want to determine whether the file exists, please use the independent function is_file(filepath)
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is_file only determines whether the file exists;
file_exists determines whether the file exists or whether the directory exists;
is_dir determines whether the directory exists;

Looking at the manual, although the results of these two functions will be cached, is_file is N times faster.
There is another thing worth noting:
When the file exists, is_file is N times faster than file_exists;
When the file does not exist, is_file is slower than file_exists;
The conclusion is that the file_exits function does not affect the speed depending on whether the file actually exists, but the impact of is_file is greater

After reading this article about the difference between file_exists, is_file, and is_dir in PHP, I basically understand that PHP’s file_exists = is_dir + is_file.

Write a program to verify:

Execute 1000 times each and record the required time.

The file does not exist (absolute path level 5/www/hx/a/b/c/) is_file:4.1909ms

The code is as follows  代码如下 复制代码 文件存在(当前目录) is_file:0.4570ms file_exists:2.0640ms 文件存在(绝对路径3层/www/hx/a/) is_file:0.4909ms file_exists:3.3500ms 文件存在(绝对路径5层/www/hx/a/b/c/) is_file:0.4961ms file_exists:4.2100ms 文件不存在(当前目录) is_file:2.0170ms file_exists:1.9848ms 文件不存在(绝对路径5层/www/hx/a/b/c/) is_file:4.1909ms file_exists:4.1502ms 目录存在 file_exists:2.9271ms is_dir:0.4601ms 目录不存在 file_exists:2.9719ms is_dir:2.9359ms

Copy code

File exists (current directory) is_file:0.4570ms file_exists:2.0640ms The file exists (absolute path level 3/www/hx/a/) is_file:0.4909ms file_exists:3.3500ms The file exists (absolute path level 5/www/hx/a/b/c/) is_file:0.4961ms file_exists:4.2100ms File does not exist (current directory) is_file:2.0170ms file_exists:1.9848ms

file_exists:4.1502ms

Directory exists

When the file exists, is_file is much faster than file_exists; The deeper the directory where the file is to be detected, the greater the speed difference, but it is at least 4 times faster. When the file does not exist, is_file is a little slower than file_exists, but it can be ignored. When the directory exists, is_dir is much faster than file_exists; When the directory does not exist, is_dir is a little slower than file_exists, but it can be ignored. Conclusion: If you want to determine whether the file exists, use the function is_file(), If you want to determine whether the directory exists, use the function is_dir(), There seems to be no place to use file_exists. Is it used when you are not sure whether the parameter passed in is a file or a directory? http://www.bkjia.com/PHPjc/633102.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/633102.htmlTechArticlePerformance analysis of is_dir, is_file, file_exists functions in php. We summarize the usage of the three functions from each method. Students in need can refer to specific places. is_dir,is_fi... in php