Modules in Python

A module is a file that contains Python code such as functions, variables, and classes. Modules help you organize and reuse code efficiently.

💡 Python modules allow you to write code once and use it anywhere.

Using Built-in Modules

Python comes with many built-in modules like math, random, and datetime. 

import math

print(math.sqrt(25))
print(math.pi)

Different Ways to Import Modules

1. Import entire module

import random

print(random.randint(1, 10))

2. Import specific items

from math import sqrt, pi

print(sqrt(16))
print(pi)

3. Import with alias

import datetime as dt

print(dt.date.today())

Creating Your Own Module

You can create your own module by saving Python code in a .py file. 

# file: calculator.py
def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

Using your custom module:

import calculator

print(calculator.add(5, 3))
print(calculator.subtract(10, 4))

Exploring Modules

Use dir() and help() to explore module contents. 

import math

print(dir(math))
help(math)

Practice Exercises

  1. Use the random module to generate a number between 1 and 100
  2. Import only sqrt from the math module
  3. Create a module that converts Celsius to Fahrenheit
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