File Handling in Python – Read, Write, Append

What is File Handling in Python?

File handling in Python allows you to create, read, write, and append to files directly from your Python code. Python provides built-in functions to perform these operations using the open() function.

Python open() Function Syntax

open(file_name, mode)

File Modes

• 'r' - Read (default)
• 'w' - Write (overwrite)
• 'a' - Append
• 'x' - Create a new file
• 'b' - Binary mode
• 't' - Text mode (default)
• '+' - Read and write

Reading a File in Python

# file: sample.txt
# Content:
# Hello, Python World!

f = open('sample.txt', 'r')
content = f.read()
print(content)
f.close()

Output:

Hello, Python World!

Pro Tip:

You can also use:

with open('sample.txt', 'r') as f:
    content = f.read()

This automatically closes the file after reading.

Writing to a File in Python

f = open('sample.txt', 'w')
f.write('This will overwrite the file.\n')
f.write('Line two.')
f.close()

Result in sample.txt:

This will overwrite the file.
Line two.

Note: The 'w' mode clears existing content before writing.

Appending to a File in Python

f = open('sample.txt', 'a')
f.write('\nThis line is appended.')
f.close()

Result in sample.txt:

This will overwrite the file.
Line two.
This line is appended.

Reading Line by Line

with open('sample.txt', 'r') as f:
    for line in f:
        print(line.strip())

Output:

This will overwrite the file.
Line two.
This line is appended.

Deleting a File

import os

if os.path.exists("sample.txt"):
    os.remove("sample.txt")
else:
    print("File does not exist")

Best Practices for File Handling

• Always use with open() — it handles closing automatically.
• Use try-except to catch file errors.
• Prefer relative paths for portability.