How to check if a file or directory exists in Python

This article presents different ways how to check if a file or a directory exists in Python.

When you want to open a file and the corresponding file or directory of the given path does not exists, Python raises an Exception. You should address this, otherwise your code will crash.

This article presents different ways how to check if a file or a directory exists in Python, and how to open a file safely.

Use a try-except block¶

First of all, instead of checking if the file exists, it’s perfectly fine to directly open it and wrap everything in a try-except block. This strategy is also known as EAFP (Easier to ask for forgiveness than permission) and is a perfectly accepted Python coding style.

 try:
    f = open("filename.txt")
 except FileNotFoundError:
     # doesn’t exist
 else:
     # exists

#more

Note: In Python 2 this was an IOError.

Use os.path.isfile(), os.path.isdir(), or os.path.exists()¶

If you don’t want to raise an Exception, or you don’t even need to open a file and just need to check if it exists, you have different options. The first way is using the different methods in os.path:

• os.path.isfile(path): returns True if the path is a valid file
• os.path.isdir(path): returns True if the path is a valid directory
• os.path.exists(path) : returns True if the path is a valid file or directory

import os

if os.path.isfile("filename.txt"):
    # file exists
    f = open("filename.txt")

if os.path.isdir("data"):
    # directory exists

if os.path.exists(file_path):
    # file or directory exists

Use Path.is_file() from pathlib module¶

Starting with Python 3.4, you can use the pathlib module. It offers an object-oriented approach to work with filesystem paths, and this is now my preferred way of dealing with files and directories.

You can create a Path object like this:

from pathlib import Path

my_file = Path("/path/to/file")

Now you can use the different methods is_file(), is_dir(), and exists() on the Path object:

if my_file.is_file():
    # file exists

if my_file.is_dir():
    # directory exists

if my_file.exists():
    # file or directory exists