PHP--Determine if a file exists

File_exists

Is_file

Is_dir

Basically, php file_exists = is_dir + is_file

Write the program to verify:

Execute 1000 times and record the time required.

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Is_file and file_exists

File exists (current directory)
Is_file:0.4570ms
File_exists:2.0640ms

File exists (absolute path 3 layer/www/hx/a/)
Is_file:0.4909ms
File_exists:3.3500ms

File exists (absolute path 5 layer/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 does not exist (absolute path 5 layer/www/hx/a/b/c/)
Is_file:4.1909ms
File_exists:4.1502ms

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Is_dir and File_exists

Directory exists
File_exists:2.9271ms
Is_dir:0.4601ms
Directory does not exist
File_exists:2.9719ms
Is_dir:2.9359ms

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Is_file ($file)
File_exists ($file)
When $file is a directory, Is_file returns false,file_exists true

In the case of a file, Is_file is much faster than file_exists;
The deeper the directory in which the file is to be detected, the greater the speed difference, but at least 4 times times faster.

If the file does not exist, Is_file is a little slower than file_exists, but it can be ignored.

In the case of directory existence, Is_dir is much faster than file_exists;
If 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 if a file exists, use the function is_file (),

If you want to determine if the directory exists, use the function Is_dir (),

Not sure if the parameter passed in is a file or a directory, use file_exists.

PHP--Determine if a file exists