PHP to determine whether the file exists using Is_file or file_exists? _php Tips

Do you use Is_file or file_exists to determine whether a file exists?

In writing procedures found in the determination of the existence of documents, there are two ways to write, some people used is_file, some people use file_exists, which 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 a program to verify:

Execute 1000 times separately to record the time required.

File exists (current directory)

Copy Code code as follows:

Is_file:0.4570ms
File_exists:2.0640ms

File exists (absolute path 3-layer/www/hx/a/)

Copy Code code as follows:

Is_file:0.4909ms
File_exists:3.3500ms

File exists (absolute path 5-layer/www/hx/a/b/c/)

Copy Code code as follows:

Is_file:0.4961ms
File_exists:4.2100ms

File does not exist (current directory)

Copy Code code as follows:

Is_file:2.0170ms
File_exists:1.9848ms

File does not exist (absolute path 5-layer/www/hx/a/b/c/)

Copy Code code as follows:

Is_file:4.1909ms
File_exists:4.1502ms

Directory exists

Copy Code code as follows:

File_exists:2.9271ms
Is_dir:0.4601ms

Directory does not exist

Copy Code code as follows:

File_exists:2.9719ms
Is_dir:2.9359ms

Is_file ($file)
File_exists ($file)

Is_file returns False,file_exists returns True when $file is a directory

In the case of files, Is_file is much faster than file_exists;
The deeper the directory you want to detect, the worse the speed, but at least 4 times times faster.

If the file does not exist, the is_file is a little slower than the file_exists, but can be negligible.

In the case of directory existence, Is_dir is much faster than file_exists;
If the directory does not exist, the is_dir is a little slower than the file_exists, but can be negligible.

Conclusion:

If you want to determine whether a 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, not sure if the incoming parameter is a file or a directory?

Attached test procedure:

Copy Code code as follows:

function Runtime ($t 1) {
Return Number_format ((Microtime (True)-$t 1) *1000, 4). ' Ms ';
}
$times = 1000;

$t 1 = microtime (true);
for ($i =0; $i < $times; $i + +) {
Is_file ('/www/hx/www.9enjoy.com/config.php ');
}

Echo ' <br>is_file: '. Runtime ($t 1);

$t 2 = Microtime (true);
for ($i =0; $i < $times; $i + +) {
File_exists ('/www/hx/www.9enjoy.com/config.php ');
}
Echo ' <br>file_exists: '. Runtime ($t 2);

/*
$t 3 = Microtime (true);
for ($i =0; $i < $times; $i + +) {
Is_dir ('/www/hx/www.9enjoy.com/');
}
Echo ' <br>is_dir: '. Runtime ($t 3);
*/