Introduction to the differences between file_exists, is_file, and is_dir in PHP_PHP Tutorial

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)

is_file only determines whether the file exists;
file_exists determines whether the file or directory exists;
is_dir determines whether the directory exists;

Check the manual. Although the results of these two functions will be cached, is_file is N times faster.
One more 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 file_exits The function does not affect the speed depending on whether the file actually exists, but the impact of is_file is great.