Modules & Packages

Modules are Python files. Packages are directories with __init__.py.

Import Styles

• import math
• from math import sqrt
• import numpy as np

pip

pip install package_name installs from PyPI.

Syntax

PYTHON

1
2
3
4
5
6
7

import math
from random import randint, choice
import datetime as dt

# Custom module
# my_module.py
def greet(name): return f"Hello, {name}!"

Python Modules and Imports

PYTHON

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21

# Import a module
import math
print("Pi:", math.pi)
print("Sqrt:", math.sqrt(25))

import os
print("Platform:", os.name)

from datetime import datetime
now = datetime.now()
print("Now:", now)
print("Year:", now.year)

from random import randint
print("Random:", randint(1, 10))

# Alias
import statistics as stats
heights = [170, 165, 180, 175]
print("Mean:", stats.mean(heights))
print("Median:", stats.median(heights))

Try It Yourself

Practice

1

Exercise

Create a calculator module and import it.

Answer

# calculator.py
def add(a,b): return a+b
# main.py
from calculator import add
print(add(3,5))

Quick Quiz

1

What file marks a directory as a package?

__main__.py

__init__.py

__init__.py marks a package directory.

Retry Quiz

Interview Questions

import vs from...import?

import loads entire module (module.func). from imports specific items directly (func).

Previous

File Handling

Tutorial Complete

Back to Python