Python Standard Library Overview

The Python Standard Library is a collection of ready-to-use modules that come installed with Python. You can use these modules to perform common tasks — without installing any third-party packages.

The Standard Library includes tools for:

File I/O String handling Math and statistics Dates and times Data structures Regular expressions Networking Concurrency and much more.

Why Use the Standard Library?

How to Access Standard Library Modules

import module_name

Example 1: math — Mathematical Functions

import math
 
print("Pi:", math.pi)
print("Square root of 16:", math.sqrt(16))

Pi: 3.141592653589793
Square root of 16: 4.0

Example 2: datetime — Dates and Times

import datetime
 
today = datetime.date.today()
print("Today's date:", today)

Today's date: 2025-06-16  # Example date

Example 3: random — Random Numbers

import random
 
print("Random number between 1 and 10:", random.randint(1, 10))

Random number between 1 and 10: 7  # Example output

Example 4: os — Operating System Interface

import os
 
print("Current working directory:", os.getcwd())

Current working directory: /Users/username/projects  # Example output

Example 5: sys — System-specific Parameters

import sys
 
print("Python version:", sys.version)

Python version: 3.12.2 (example)

Example 6: statistics — Basic Stats

import statistics
 
data = [10, 20, 30, 40, 50]
print("Mean:", statistics.mean(data))
print("Median:", statistics.median(data))

Mean: 30
Median: 30

Other Useful Modules (Partial List)

Summary

• The Standard Library is a powerful collection of pre-installed modules.
• No installation required — just import and use.
• Helps you write better, faster, more portable Python code.

In the next section, we will explore Writing Your Own Modules — how to structure your code into reusable modules.