Modules and Packages

What is a Module?

A module is a Python file containing functions, classes, and variables that you can import.

Importing Modules

# Import entire module
import math
print(math.pi)       # 3.141592653589793
print(math.sqrt(16)) # 4.0
Import specific items
from math import pi, sqrt
print(pi)    # 3.141592653589793
print(sqrt(16))  # 4.0
Import with alias
import math as m
print(m.pi)

Standard Library Modules

datetime

import datetime
now = datetime.datetime.now()
print(now)  # 2024-01-15 10:30:45

random

import random
print(random.randint(1, 10))    # Random int 1-10
print(random.choice(['a', 'b', 'c']))  # Random choice
print(random.shuffle([1, 2, 3]))  # Shuffle list

json

import json
data = {"name": "John", "age": 30}
json_str = json.dumps(data)     # Dict to JSON string
parsed = json.loads(json_str)   # JSON string to dict

Creating Your Own Module

mymodule.py

# mymodule.py
def greet(name):
    return f"Hello, {name}!"
def add(a, b):
    return a + b

Using Your Module

import mymodule
print(mymodule.greet("John"))  # Hello, John!
print(mymodule.add(3, 5))       # 8

Packages

A package is a directory containing multiple modules.

mypackage/
    __init__.py
    module1.py
    module2.py

__init__.py

This file makes a directory a package. It can also set up imports:

# mypackage/__init__.py
from .module1 import func1
from .module2 import func2

Using Packages

from mypackage import func1
func1()

pip - Package Manager

# Install package
pip install requests
List installed packages
pip list
Uninstall
pip uninstall requests

Summary

• Modules: Python files with reusable code
• Import: use other modules
• Packages: directories of modules
• pip: install external packages

Congratulations!

You've completed the Python basics course! Keep practicing and building projects.