3 Best Methods to Check if File or Directory Exist in Python

Many times in the program we need to handle reading and writing files. I am sure you might have come across when your program crashes if the file in the directory that you want to read does not exist.

And this happens to everyone if you start learning file handling in Python.

So the only solution to avoid a crash is using “Python check if file exists or not before performing any operations on file”.

In this tutorial, I am sharing with you three different ways of checking file and directory existence before reading or writing it.

Using…

• os Python module
• try block
• pathlib Python module

If you are new to the file handling in Python, here is a code for reading the file in Python. (This code is written to read csv file format but it works for reading any type of file.)

Now let’s come to the topic…

How to write code for Python to check if a file exists?

Here are three different methods you can use…

1. Using os Python module

The os module has a method os.path.exists() to check the file’s existence in the directory.

Python Check if File Exist

import os

print(os.path.exists(test_file.txt))
#True

print(os.path.exists(no_exist_file.txt))
#False

Python Check if Directory Exist

import os

print(os.path.exists(test_dir))
#True

print(os.path.exists(no_exist_dir))
#False

There can be a file and directory with the same name. If you check using the above methods, you can not identify whether it is a file or a directory.

Suppose you want to check if file “test-data” is present or not. In case there is a directory with the name “test-data”, the above functionos.path.exists() will return True. This is not expected as you are interested in the file (not the directory).

To avoid this teeter, you can use the following method.

Code for Checking only Files:

import os
os.path.isfile("test-data")

The above method will return False if there is no file “test-data”, even if the directory is present with the same name.

Even if the file is present, you can find whether the file is accessible to write or to execute.

How to check if the File is Accessible to read, write or execute?

You can check the file if it is accessible for the various modes of accessing the file (ex. read, write or execute) using the method os.access().

Syntax:

os.access(<path>, <mode>)

Along with the file path, you can provide accessible mode:

• os.F_OK: to check the existence of the file path
• os.R_OK: to check if the file is accessible to read
• os.W_OK: to check if the file is accessible to write
• os.X_OK:  to check if the file is accessible to execute

This method returns True or False based on the existence of the file path and permission to access the various accessible modes.

import os

if os.access("/file/path/foo.txt", os.F_OK):
    print("Given file path is exist.")

if os.access("/file/path/foo.txt", os.R_OK):
    print("File is accessible to read")

if os.access("/file/path/foo.txt", os.W_OK):
    print("File is accessible to write")

if os.access("/file/path/foo.txt", os.X_OK):
    print("File is accessible to execute")

This is a very useful method if you want to check the file for a particular access mode.

2. Using try Block:

You can open the file using the method open(). It checks if the file is accessible or not in your program.

Syntax for Opening the File:

open(<file/path>)

If you open the file directly without checking its existence, the program may crash. As with general exception handling, you can use a try block to catch the exception.

There can be many reasons why you are not able to access the file in your program.

• If you are trying to open the file which is not present it will throw an exception as FileNotFoundError.
• If the file is present but if you don’t have permission to access it in your program, it throws an error as PersmissionError.

So here is a code for Python to check if the file exists…

try:
    f =open()
    #Perform File Operations (Reading and Writing a File)
    f.close()

except FileNotFoundError:
    print("File is not found.")

except PersmissionError:
    print("You don't have permission to access this file.")

You don’t need to handle all the exceptions individually. All these exceptions come under the parent exception IOError.

So you can simply write a program to handle all the file check exceptions as follows…

try:
    f =open()
    #Perform File Operations (Reading and Writing a File)
    f.close()

except IOError:
    print("File is not accessible.")

Using a try block for Python to check if the file exists is very simple and graceful to handle all the exceptions.

Doing it more Pythonic way (as per Vernon Cole explained in the comment)…

myfilename = "my_file.txt"

try:
    with open(myfilename) as myfile:
        for line in myfile:
            print(line.strip())

except IOError:
    print("Trouble using file {}".format(myfilename))

And the good thing is… you don’t need to import any external module to use it.

3. Using pathlib Python module

The module pathlib is available in Python 3. If you are using Python 2 version, you can install it as 3rd party module.

First, you have to create a path object by passing the path of the file. This path can be a file name or directory path.

Check if the Path is Exist or not:

path = pathlib.Path("path/file")
path
path.exist()

Check if the Path mentioned is a file or not:

path = pathlib.Path("path/file")
path
path.is_file()

This is all about this tutorial for Python to check if a file exists. If you have any doubts, feel free to write in the comment section. I will reply to your every query as soon as possible.

Other File Program you can give a try to explore File handling in Python:

• Read CSV file | With Example
• Find the longest line from a file in the Python Program

Happy coding!

Aniruddha Chaudhari

I am complete Python Nut, love Linux and vim as an editor. I hold a Master of Computer Science from NIT Trichy. I dabble in C/C++, Java too. I keep sharing my coding knowledge and my own experience on <b>CSEstack.org</b> portal.