📂 File Handling in Python

🔍 What is File Handling?

File handling in Python allows you to create, read, update, and delete files directly from your Python code. It is crucial when working with external data, logs, or reports.

📁 File Modes in Python

• 'r' – Read (default): Opens file for reading, error if file doesn’t exist.
• 'w' – Write: Creates a new file or truncates existing one.
• 'a' – Append: Opens file for appending data to end.
• 'x' – Create: Creates file, fails if file already exists.
• 'b' – Binary mode (e.g., 'rb' or 'wb')
• 't' – Text mode (default)

🛠 Basic File Operations

📖 1. Opening and Reading a File

file = open("example.txt", "r")
content = file.read()
print(content)
file.close()

✍️ 2. Writing to a File

file = open("example.txt", "w")
file.write("Hello, this is a test.")
file.close()

📌 3. Appending to a File

file = open("example.txt", "a")
file.write("\nAdding a second line.")
file.close()

✅ 4. Using with for Auto-close

with open("example.txt", "r") as file:
    print(file.read())

This is the recommended way as it automatically closes the file.

💡 Use Cases

• Reading configuration or log files
• Saving form submissions or reports
• Creating logs for user activity or errors
• Handling data imports or exports in CSV format

📚 Best Practices

• Always close the file or use with context manager
• Handle exceptions with try...except
• Validate file existence using os.path.exists()

🔗 References

• Python Docs – Reading and Writing Files
• W3Schools – File Handling