Python Check If File Exists
Summary: in this tutorial, you’ll learn how to check if a file exists.
When processing files, you’ll often want to check if a file exists before doing something else with it such as reading from the file or writing to it.
To do it, you can use the exists() function from the os.path module or is_file() method from the Path class in the pathlib module.
os.path.exists() function
from os.path import existsfile_exists = exists(path_to_file)
Code language: JavaScript (javascript)
Path.is_file() method
from pathlib import Pathpath = Path(path_to_file)
path.is_file()
Code language: JavaScript (javascript)
1) Using os.path.exists() function to check if a file exists
To check if a file exists, you pass the file path to the exists() function from the os.path standard library.
First, import the os.path standard library:
import os.pathCode language: JavaScript (javascript)
Second, call the exists() function:
os.path.exists(path_to_file)Code language: CSS (css)
If the file exists, the exists() function returns True. Otherwise, it returns False.
If the file is in the same folder as the program, the path_to_file is just simply the file name.
However, it’s not the case, you need to pass the full file path of the file. For example:
/path/to/filename
Even if you run the program on Windows, you should use the forward-slash (/) to separate the path. It’ll work across Windows, macOS, and Linux.
The following example uses the exists() function to check if the readme.txt file exists in the same folder as the program:
import os.pathfile_exists = os.path.exists('readme.txt')
print(file_exists)
Code language: JavaScript (javascript)
If the readme.txt file exists, you’ll see the following output:
TrueCode language: PHP (php)
Otherwise, you’ll see False on the screen:
FalseCode language: PHP (php)
To make the call to the exists() function shorter and more obvious, you can import that function and rename it to file_exists() function like this:
from os.path import exists as file_existsfile_exists('readme.txt')
Code language: JavaScript (javascript)
2) Using the pathlib module to check if a file exists
Python introduced the pathlib module since the version 3.4.
The pathlib module allows you to manipulate files and folders using the object-oriented approach. If you’re not familiar with object-oriented programming, check out the Python OOP section.
First, import the Path class from the pathlib module:
from pathlib import PathCode language: JavaScript (javascript)
Then, instantiate a new instance of the Path class and initialize it with the file path that you want to check for existence:
path = Path(path_to_file)
Finally, check if the file exists using the is_file() method:
path.is_file()Code language: CSS (css)
If the file doesn’t exist, the is_file() method returns False. Otherwise, it returns True.
The following example shows how to use the Path class from the pathlib module to check if the readme.txt file exists in the same folder of the program:
from pathlib import Pathpath_to_file = 'readme.txt'
path = Path(path_to_file)
if path.is_file():
print(f'The file {path_to_file} exists')
else:
print(f'The file {path_to_file} does not exist')
Code language: PHP (php)
If the readme.txt file exists, you’ll see the following output:
The file readme.txt existsCode language: CSS (css)
Summary
- Use
os.path.exists()function orPath.is_file()method to check if a file exists