Modules — Organizing & Reusing Code

Importing built-in modules:

import math
math.sqrt(16)      # 4.0
math.pi            # 3.14159...

import random
random.randint(1, 10)   # random int 1-10
random.choice(["a","b","c"])  # random element

import os
os.getcwd()        # current directory
os.listdir(".")    # list files

import datetime
now = datetime.datetime.now()

Import styles:

from math import sqrt, pi       # import specific
from math import *               # import all (avoid)
import numpy as np               # alias
from datetime import datetime as dt

Creating your own module: Save functions in mymodule.py. Import with import mymodule or from mymodule import my_function.

Installing third-party packages:

pip install requests
pip install pandas numpy matplotlib

Reference:

Wikipedia: Modular Programming

https://en.wikipedia.org/wiki/Modular_programming