Check if a file exists in Python: os, pathlib, glob

1 1. Why Check for File Existence in Python
- 1.1 Introduction
2 2. Basic Approach: os Module
- 2.1 How to Use os.path.exists()
- 2.2 Choosing Between os.path.isfile() and os.path.isdir()
3 3. Advanced: pathlib Module
4 4. Checking File Existence in Python: How to Use the glob Module
- 4.1 Pattern Matching with glob
- 4.2 Real-World Scenario
5 5. Safe File Operations Using Exception Handling
6 6. Summary

1. Why Check for File Existence in Python

Introduction

Verifying that a file exists is essential for improving program stability. For example, when reading or writing data, if the target file does not exist, an error occurs and the program execution is halted. In Python, there are several ways to check for a file’s existence, and it’s important to choose the method best suited to the specific scenario. This article introduces file-checking methods using the os module, the pathlib module, and the glob module, and explains the advantages of each approach.

2. Basic Approach: os Module

How to Use os.path.exists()

os.path.exists() is used to check whether the specified path exists as a file or directory. This function returns True if it exists and False if it does not.

import os

if os.path.exists("example.txt"):
    print("The file exists")
else:
    print("The file does not exist")

This code checks whether example.txt exists and displays a message based on the result. os.path.exists() is a generic method that can check both files and directories.

Choosing Between os.path.isfile() and os.path.isdir()

os.path.exists() does not differentiate between files and directories, but using os.path.isfile() or os.path.isdir() allows you to determine whether the target is a file or a directory.

if os.path.isfile("example.txt"):
    print("This is a file")
elif os.path.isdir("example.txt"):
    print("This is a directory")
else:
    print("It does not exist")

In this way, after confirming the existence of the target, determining whether it is a file or a directory enables more fine-grained operations.

3. Advanced: pathlib Module

Using the Path.exists() Method

pathlib you can use the Path.exists() method to check whether a file or directory exists. Like os.path.exists(), it returns True or False, but the code becomes more concise.

from pathlib import Path

file_path = Path("example.txt")

if file_path.exists():
    print("The file exists")
else:
    print("The file does not exist")

With this approach, the file path is treated as a Path object, so the code is written in an object‑oriented way and is easier to maintain.

Path.is_file() and Path.is_dir()

pathlib also provides the is_file() and is_dir() methods, allowing you to easily distinguish whether something is a file or a directory.

if file_path.is_file():
    print("This is a file")
elif file_path.is_dir():
    print("This is a directory")

Thus, by using pathlib, you can not only check for a file’s existence but also easily determine whether the target is a file or a directory.

Real‑World Scenario

pathlib is especially useful in projects that manipulate multiple directories and files. It lets you write complex path operations simply, and because the same code works across different platforms, it’s ideal for cross‑platform development.

4. Checking File Existence in Python: How to Use the glob Module

Pattern Matching with glob

glob The module allows you to search for files based on filename or path patterns, making it handy when you want to check all files that meet certain criteria at once. It’s especially effective in scenarios involving large numbers of files.

import glob

files = glob.glob('*.txt')

if files:
    print("Text files found")
else:
    print("No text files found")

In this code, we retrieve all .txt files present in the current directory as a list and verify their existence. Because you can search for files in bulk based on specific file types or patterns, it’s useful for managing backup files and similar tasks.

Real-World Scenario

glob is suitable when working with large numbers of files or folders, or when you need to efficiently process files that match specific names or extensions. For example, it’s ideal for tasks that regularly check and manage log files or temporary files.

5. Safe File Operations Using Exception Handling

It’s also important to use exception handling to prevent errors when a file does not exist. By using the try-except syntax, you can prevent the program from stopping due to errors and display an error message to the user.

try:
    with open("example.txt") as f:
        print(f.read())
except FileNotFoundError:
    print("The file does not exist")

In this code, when a file does not exist, it catches FileNotFoundError and displays an error message without crashing the program. This improves the user experience and increases the program’s stability.

6. Summary

To check for file existence in Python, there are various approaches such as the os module, pathlib module, and glob module. Each method has advantages depending on the scenario, and it’s important to choose the appropriate one.

For simple existence checks, os.path.exists() is optimal.
When complex path manipulation or cross‑platform support is needed, pathlib is handy.
For pattern‑based searches, the glob module is effective.

By understanding and using these methods appropriately, you can perform file operations in Python efficiently and safely. As a next step, we recommend learning about reading, writing, deleting, and copying files.