PHP judge whether the file exists with file_exists or is_file

From:http://www.php100.com/html/php/hanshu/2013/0905/4672.html

[Guide] in writing procedures found in the judgment of the existence of the file, there are two ways to write, some people use the is_file, some people use the file_exists, which better or more appropriate? Does the file exist in Is_file or file_exists? When writing a program, it is found that there are two ways to determine if a file exists

In writing procedures found in the determination of the existence of files, there are two ways to write, some people use the is_file, some people use the file_exists, which is better or more appropriate?

Does the file exist in Is_file or file_exists?

In writing procedures found in the determination of the existence of files, there are two ways to write, some people use the is_file, some people use the file_exists, which is better or more appropriate?

Read this PHP file_exists and is_file,is_dir The difference between the basic understanding, PHP file_exists = Is_dir + is_file.

Write the program to verify:

Execute 1000 times and record the time required.

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

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

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 (),
It seems that there is no place to use file_exists, not sure if the parameters passed in file or directory?

PHP judge whether the file exists with file_exists or is_file