python - How do I check whether a file exists without exceptions?

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Top 5 Answer for python - How do I check whether a file exists without exceptions?

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98

If the reason you're checking is so you can do something like if file_exists: open_it(), it's safer to use a try around the attempt to open it. Checking and then opening risks the file being deleted or moved or something between when you check and when you try to open it.

If you're not planning to open the file immediately, you can use os.path.isfile

Return True if path is an existing regular file. This follows symbolic links, so both islink() and isfile() can be true for the same path.

import os.path os.path.isfile(fname)  

if you need to be sure it's a file.

Starting with Python 3.4, the pathlib module offers an object-oriented approach (backported to pathlib2 in Python 2.7):

from pathlib import Path  my_file = Path("/path/to/file") if my_file.is_file():     # file exists 

To check a directory, do:

if my_file.is_dir():     # directory exists 

To check whether a Path object exists independently of whether is it a file or directory, use exists():

if my_file.exists():     # path exists 

You can also use resolve(strict=True) in a try block:

try:     my_abs_path = my_file.resolve(strict=True) except FileNotFoundError:     # doesn't exist else:     # exists 
vote vote

86

You have the os.path.exists function:

import os.path os.path.exists(file_path) 

This returns True for both files and directories but you can instead use

os.path.isfile(file_path) 

to test if it's a file specifically. It follows symlinks.

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71

Unlike isfile(), exists() will return True for directories. So depending on if you want only plain files or also directories, you'll use isfile() or exists(). Here is some simple REPL output:

>>> os.path.isfile("/etc/password.txt") True >>> os.path.isfile("/etc") False >>> os.path.isfile("/does/not/exist") False >>> os.path.exists("/etc/password.txt") True >>> os.path.exists("/etc") True >>> os.path.exists("/does/not/exist") False 
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69

import os  if os.path.isfile(filepath):    print("File exists") 
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50

Use os.path.isfile() with os.access():

import os  PATH = './file.txt' if os.path.isfile(PATH) and os.access(PATH, os.R_OK):     print("File exists and is readable") else:     print("Either the file is missing or not readable") 

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