Python Tutorial 7.1 - Reading & Writing Files

Welcome to the “Reading & Writing Files” tutorial!

Overview

Python provides built-in functions to open, read, write, and close files.

Opening Files

# mode: 'r'=read, 'w'=write, 'a'=append, 'b'=binary
file = open('example.txt', 'r')

Reading Files

content = file.read()        # entire file as a string
line = file.readline()       # one line
lines = file.readlines()     # list of lines

Writing Files

with open('output.txt', 'w') as file:
    file.write('Hello, World!\n')
    file.writelines(['Line 1\n', 'Line 2\n'])

Closing Files

file = open('data.txt', 'r')
# ... work with file ...
file.close()

Tip: It’s safest to use with so files are closed automatically.

Key Takeaways

• Use open() with the correct mode.
• Always close files or use with open(...).
• Reading methods: .read(), .readline(), .readlines().
• Writing methods: .write(), .writelines().

Happy coding!