Advanced Python · Week 3

Tuples

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Exercise 1: Introduction to Tuples

Welcome to Python 2, Lesson 3! Today, we'll learn about tuples, another important data structure in Python.

What is a Tuple?

A tuple is an ordered, immutable collection of elements. This means once you create a tuple, you can't change its contents.

Here's how to create a simple tuple:

# Create a tuple of fruits
fruits = ("apple", "banana", "cherry")

print(fruits)
print(type(fruits))

Now it's your turn! Create a tuple called colors with the following items:

red
green
blue

After creating the tuple, print it and its type to see the result.

Starter code

# Create the colors tuple here

# Print the tuple and its type

Write your code here

python

# Create the colors tuple here

# Print the tuple and its type

Exercise 2: Accessing Tuple Elements

Now that we've created a tuple, let's learn how to access its elements.

Accessing Tuple Elements

Use square brackets and the index: tuple_name[index]
Indexing starts at 0
Negative indices count from the end (-1 is the last element)

Here's an example:

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

print(fruits[0])  # First element
print(fruits[-1])  # Last element
print(fruits[1:])  # Slice: second element to the end

Your turn! Using the colors tuple from the previous exercise:

Print the second color in the tuple
Print the last color using a negative index
Print a slice of the tuple containing the first two colors

Starter code

colors = ("red", "green", "blue")

# Your code here

Write your code here

python

colors = ("red", "green", "blue")

# Your code here

Exercise 3: Tuple Methods and Operations

Tuples have fewer methods than lists because they're immutable, but there are still some useful operations we can perform.

Common Tuple Operations

len(tuple): Returns the number of elements in the tuple
tuple.count(value): Counts how many times a value appears in the tuple
tuple.index(value): Returns the index of the first occurrence of a value
+ operator: Concatenates tuples
* operator: Repeats a tuple

Here's an example:

numbers = (1, 2, 3, 2, 4, 2)

print(len(numbers))
print(numbers.count(2))
print(numbers.index(4))

combined = numbers + (5, 6)
repeated = numbers * 2

print(combined)
print(repeated)

Your task:

Create a tuple called pets with the values "dog", "cat", "fish", "cat"
Print the length of the pets tuple
Count how many times "cat" appears in the tuple
Find the index of "fish" in the tuple
Create a new tuple by concatenating pets with ("hamster", "bird")

Starter code

# Create the pets tuple and perform the required operations

Write your code here

python

# Create the pets tuple and perform the required operations

Exercise 4: Tuples vs Lists

Now that we've learned about tuples, let's compare them with lists to understand when to use each.

Tuples vs Lists

Tuples are immutable (can't be changed), lists are mutable
Tuples use parentheses (), lists use square brackets []
Tuples are faster for accessing elements
Lists are better when you need to modify the collection

Here's an example showing some differences:

# Tuple
coordinates = (3, 4)
# coordinates[0] = 5  # This would raise an error

# List
scores = [85, 90, 78]
scores[1] = 92  # This is allowed

print(coordinates)
print(scores)

Your task:

Create a tuple person with name and age (e.g., "Alice", 30)
Create a list hobbies with some hobbies
Try to add a new hobby to the list
Try to change the age in the tuple (this will cause an error, but it's okay!)
Print both the tuple and the list

Starter code

# Create a tuple and a list, then try modifying them

Write your code here

python

# Create a tuple and a list, then try modifying them

Weekly Project: Student Records

Let's put everything we've learned about tuples into practice by creating a simple student record system.

Your task is to create a program that:

Stores student information (name, age, grade) in tuples
Keeps a list of these student tuples
Allows adding new students
Displays all student records
Finds a student by name

Here's a starting template:

def add_student(students, name, age, grade):
    # Your code here
    pass

def display_students(students):
    # Your code here
    pass

def find_student(students, name):
    # Your code here
    pass

# Main program
students = []

while True:
    print("\n1. Add student")
    print("2. Display all students")
    print("3. Find student")
    print("4. Exit")
    
    choice = input("Enter your choice (1-4): ")
    
    # Implement the menu options here
    
    if choice == '4':
        break

print("Thank you for using the Student Records system!")

Implement the functions and the main program loop. Use tuples to store each student's information and a list to keep track of all students.

This project will give you hands-on experience with tuples and reinforce the concepts we've covered this week. Good luck!

Starter code

# Implement your Student Records system here

Write your code here

python

# Implement your Student Records system here

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