Check File Existence with Python Pathlib.exists()

Python's pathlib module simplifies file path handling. One of its useful methods is exists(). It checks if a file or directory exists.

This article explains how to use pathlib.exists() effectively. We'll cover its syntax, usage, and examples.

What is pathlib.exists()?

The exists() method is part of the Path class in the pathlib module. It returns True if the path exists, otherwise False.

This method is handy for verifying files or directories before performing operations. It prevents errors like FileNotFoundError.

Syntax of pathlib.exists()

The syntax is straightforward. You create a Path object and call exists() on it.

from pathlib import Path

# Create a Path object
path = Path("example.txt")

# Check if the file exists
if path.exists():
    print("File exists!")
else:
    print("File does not exist.")
    

In this example, the code checks if example.txt exists in the current directory.

Example: Checking File Existence

Let's see a practical example. Suppose you have a file named data.csv.

from pathlib import Path

# Define the file path
file_path = Path("data.csv")

# Check if the file exists
if file_path.exists():
    print(f"{file_path} exists.")
else:
    print(f"{file_path} does not exist.")
    

If data.csv exists, the output will be:

data.csv exists.
    

If it doesn't exist, the output will be:

data.csv does not exist.
    

Example: Checking Directory Existence

The exists() method also works for directories. Let's check if a directory named docs exists.

from pathlib import Path

# Define the directory path
dir_path = Path("docs")

# Check if the directory exists
if dir_path.exists():
    print(f"{dir_path} exists.")
else:
    print(f"{dir_path} does not exist.")
    

If the docs directory exists, the output will be:

docs exists.
    

If it doesn't exist, the output will be:

docs does not exist.
    

Combining pathlib.exists() with Other Methods

You can combine exists() with other pathlib methods. For example, use joinpath() to build paths dynamically.

from pathlib import Path

# Define a base directory
base_dir = Path("projects")

# Create a dynamic path
file_path = base_dir.joinpath("data", "example.txt")

# Check if the file exists
if file_path.exists():
    print(f"{file_path} exists.")
else:
    print(f"{file_path} does not exist.")
    

This code checks if example.txt exists in the projects/data directory.

Handling Relative and Absolute Paths

The exists() method works with both relative and absolute paths. Use resolve() to convert relative paths to absolute paths.

from pathlib import Path

# Define a relative path
relative_path = Path("example.txt")

# Convert to absolute path
absolute_path = relative_path.resolve()

# Check if the file exists
if absolute_path.exists():
    print(f"{absolute_path} exists.")
else:
    print(f"{absolute_path} does not exist.")
    

This ensures the path is correctly interpreted, especially in complex projects.

Conclusion

The pathlib.exists() method is a powerful tool for checking file and directory existence. It's easy to use and integrates well with other pathlib methods.

By mastering exists(), you can write more robust Python scripts. Always verify paths before performing operations to avoid errors.

For more tips on handling file paths, check out our guides on joinpath() and resolve().