Objective

In this unit, we will learn about ranges, sets, and tuples in Python. These are three types of data structures that can be used to store multiple items. By the end of this unit, you will understand how to use these data structures and know the differences between them and lists.

Ranges

A range in Python is a sequence of numbers that is immutable (unchangeable) and often used in for loops to repeat an action a certain number of times.

Here's an example of creating a range and converting it to a list:

numbers = list(range(10))
print(numbers)

This code will output the numbers from 0 to 9. The range function generates a sequence of numbers starting from 0 by default, and stops before a specified number.

Sets

A set in Python is an unordered collection of items that is iterable, mutable, and has no duplicate elements. Python’s set class represents the mathematical notion of a set.

Here's an example of creating a set:

fruits = {"apple", "banana", "cherry"}
print(fruits)

This code will output {'cherry', 'banana', 'apple'}. Note that sets are unordered, so the items will appear in a random order.

Tuples

A tuple in Python is similar to a list. The difference between the two is that tuples are immutable, which means you can't change elements of a tuple once it is assigned. On the other hand, lists are mutable.

Here's an example of creating a tuple:

fruits = ("apple", "banana", "cherry")
print(fruits)

This code will output ('apple', 'banana', 'cherry').

Differences Between Lists, Sets, and Tuples

• Lists are ordered, mutable, and allow duplicate elements. They are defined by having values between square brackets [].
• Sets are unordered, mutable, and do not allow duplicate elements. They are defined by having values between curly braces {}.
• Tuples are ordered, immutable, and allow duplicate elements. They are defined by having values between parentheses ().

Project: Create a Program Where a Range Controls the Size of a Shape, a Set Controls the Colors, and a Tuple Controls the Position

In this project, we will use a range, a set, and a tuple to control different aspects of a turtle drawing.

import turtle

# Create a new turtle screen and set its background color
screen = turtle.Screen()
screen.setup(width=800, height=600)
screen.bgcolor("white")

# Initialize a turtle object
t = turtle.Turtle()

# Define a range for the size of the shapes
sizes = range(50, 150, 20)

# Define a set for the colors of the shapes
colors = {"red", "green", "blue", "orange", "purple"}

# Define a tuple for the starting position of the turtle
start_pos = (-200, 0)

# Move the turtle to the starting position
t.penup()
t.goto(start_pos)
t.pendown()

# Use a for loop to draw the shapes
for size in sizes:
    t.color(colors.pop())  # Remove and return a random color from the set
    for _ in range(4):
        t.forward(size)
        t.right(90)
    t.penup()
    t.forward(size + 20)  # Move to the right before drawing the next shape
    t.pendown()

# Hide the turtle and wait until the window is closed
t.hideturtle()
turtle.done()

In this code, we use a range to control the size of the squares that the turtle draws, a set to control the colors of the squares, and a tuple to control the starting position of the turtle. We use a for loop to draw each square, and the pop method of the set to remove and return a random color for each square.

Try modifying the range, set, and tuple to create different patterns!

In the next unit, we'll look at dictionaries and explore how to use this powerful data structure in Python.