Using Other Modules

Every time we want to draw with a Python turtle, we import the turtle module. A module is an extra set of code that extends the general functionality of the Python language. Through this course, we will use several other modules, including math and random in this unit, and numpy, matplotlib, and pandas in the second semester.

There are a number of modules (also called libraries) that come with a normal installation of Python. There are also many third-party Python modules. To see a list of all the modules that come with Python by default, first go to the Python documentation page, then click on the “Global Module Index” link to see a list of all the default Python libraries. Clicking on the titles of any of these modules will open the documentation page for the modules.

In-Class Problem: Math Module

Use the Global Module Index (a.k.a. the “Globulex”) to open the documentation page for the math module. Scroll down the page to see all the methods and constants this module contains. Find the methods called math.pi and math.factorial().

Then, solve these two problems:

  1. Write a Python program with a function that uses math.pi to calculate the circumference of a circle.
  2. Add another function to the program that calculates the factorial value of any integer. Remember that 4! = 1 * 2 * 3 * 4.

Make sure you’ve written your own solution before looking at the solution below:

import math

def circumference(radius):
    return math.pi * radius ** 2

def factorial(integer):
    return math.factorial(integer)  # how would you write this function WITHOUT the math module?

print("The circumference of a circle with radius 2 is", circumference(2))
print("5! =", factorial(5))

The Random Module

Use the Global Modular Index to open the documentation page for the random module. Find the documentation notes for random.randrange(), random.randit(), random.random(), and random.choice().

Then, solve these problems:

  1. Write a Python program with a function that uses the random module to generate a random odd integer between -1000 and 1000.
  2. Add another functdion to that the program to simulate drawing a random card from a 52-card deck. (Hint: use random.choice() twice for this.)
import random

def rand_integer(lowest, highest):
    return random.randint(lowest, highest)

def random_card():      # no parameters are needed
    value = random.choice(["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "Jack", "Queen", "King", "Ace"])
    suit = random.choice(["Clubs", "Spades", "Diamonds", "Hearts"])
    card = "the", value, "of", suit

    return (card)

Homework:

  1. Read HTCS, 5.1-5.4
  2. Write a Python program that calculates the area of a circle with a randomly-generated radius between 1 and 100 units. Use both the math module and the random module in your solution. Submit your answer to the Petra Portal.