Code-Memo

File Handling and Input/Output Operations

Working with Binary Data

Python allows you to read and write binary data using file objects opened in binary mode ('rb' for reading and 'wb' for writing).

• Reading Binary Data:

with open('binary_file.bin', 'rb') as file:
    data = file.read()
    # Process binary data

• Writing Binary Data:

data = b'\x48\x65\x6c\x6c\x6f'  # Example binary data
with open('binary_file.bin', 'wb') as file:
    file.write(data)

Contextlib and Pathlib Modules

contextlib Module

The contextlib module provides utilities for working with context managers, simplifying the creation of context managers using generators and decorators.

• Example: Using contextlib for managing resources:

import contextlib

@contextlib.contextmanager
def open_file(filename):
    file = open(filename, 'r')
    try:
        yield file
    finally:
        file.close()

# Usage:
with open_file('example.txt') as file:
    content = file.read()
    print(content)

pathlib Module

The pathlib module provides an object-oriented approach to working with filesystem paths. It offers a more readable and convenient way to manipulate files and directories compared to traditional string-based operations.

• Example: Using pathlib for file operations:

from pathlib import Path

# Read file content
file_path = Path('example.txt')
content = file_path.read_text()
print(content)

# Write to file
new_content = 'New content'
file_path.write_text(new_content)

File Locking and Atomic Writes

File Locking

File locking ensures that a file is not accessed or modified by multiple processes simultaneously, preventing data corruption or conflicts.

• Using fcntl module for file locking (Unix-like systems):

import fcntl

with open('data.txt', 'a') as file:
    fcntl.flock(file, fcntl.LOCK_EX)  # Acquire exclusive lock
    file.write('New data\n')
    fcntl.flock(file, fcntl.LOCK_UN)  # Release lock

Atomic Writes

Atomic writes ensure that a file write operation is either fully completed or not at all, avoiding partial writes or corrupted data in case of interruptions.

• Using temporary file and renaming for atomic writes:

import os
import tempfile

filename = 'data.txt'
temp_filename = filename + '.tmp'

# Write data to temporary file
with open(temp_filename, 'w') as temp_file:
    temp_file.write('New data\n')

# Atomic write by renaming temporary file
os.replace(temp_filename, filename)

Benefits of File Handling and I/O Operations

• Data Integrity: Ensures data is read and written correctly without corruption.
• Concurrency: Handles multiple processes accessing files concurrently using file locking.
• Code Readability: pathlib provides a more readable and intuitive API for working with filesystem paths.