Python File Handling

File Handling allows you to create, read, write, and manage files in Python. Python provides the built-in open() function to work with files.

Opening a File

The open() function is used to open a file.

Syntax

open(file_name, mode)

Example

file = open("sample.txt", "r")

File Modes

Mode	Description
r	Read file
w	Write file (overwrites existing content)
a	Append data to file
x	Create a new file
r+	Read and write
b	Binary mode
t	Text mode (default)

Reading a File

Example

file = open("sample.txt", "r")

print(file.read())

file.close()

Output:

Hello Python

Reading a Specific Number of Characters

Example

file = open("sample.txt", "r")

print(file.read(5))

file.close()

Output:

Hello

Reading a Single Line

Example

file = open("sample.txt", "r")

print(file.readline())

file.close()

Output:

Hello Python

Reading All Lines

Example

file = open("sample.txt", "r")

print(file.readlines())

file.close()

Output:

['Hello Python\n', 'Welcome']

Loop Through a File

Example

file = open("sample.txt", "r")

for line in file:
    print(line)

file.close()

Writing to a File

The w mode creates a file if it does not exist and overwrites existing content.

Example

file = open("sample.txt", "w")

file.write("Hello Python")

file.close()

Appending to a File

The a mode adds content to the end of a file.

Example

file = open("sample.txt", "a")

file.write("\nWelcome")

file.close()

Using with Statement

The with statement automatically closes the file.

Example

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

Output:

Hello Python
Welcome

Check if File Exists

Example

import os

if os.path.exists("sample.txt"):
    print("File exists")
else:
    print("File not found")

Output:

File exists

Summary

• open() is used to work with files.
• File modes determine how a file is accessed.
• read(), readline(), and readlines() are used to read file content.
• write() writes data to a file.
• append() mode adds data without removing existing content.
• close() closes a file after use.
• The with statement automatically handles file closing.
• File existence can be checked using the os module.