Python Docs

Python File Reading — Full Cheat Sheet

What is File Handling?

Python uses the open() function to handle files. It returns a file object that allows reading, writing, or modifying files.

open() Syntax

open(filename, mode)

Common File Modes

  • r – Read (default)
  • a – Append
  • w – Write
  • x – Create
  • t – Text mode (default)
  • b – Binary mode

Basic File Reading

Reads the entire file content.

f = open("demofile.txt", "r")
print(f.read())

Reading From a File Path

f = open("D:\\myfiles\\welcome.txt")
print(f.read())

Using the with Statement

with automatically closes the file after use. It is the recommended way to work with files.

with open("demofile.txt") as f:
  print(f.read())

Closing Files

If you don't use with, always call close().

f = open("demofile.txt")
print(f.readline())
f.close()

Reading Only Part of the File

Specify the number of characters inside read(n).

with open("demofile.txt") as f:
  print(f.read(5))   # Reads 5 characters

Reading Lines

Read One Line

with open("demofile.txt") as f:
  print(f.readline())

Read Two Lines

with open("demofile.txt") as f:
  print(f.readline())
  print(f.readline())

Loop Through File Line-by-Line

with open("demofile.txt") as f:
  for line in f:
    print(line)

Summary

  • open() creates a file object
  • read() reads entire file or first n characters
  • readline() reads one line
  • loop to read file line-by-line
  • with auto-closes file
  • close() closes manually when not using with