Multiple return values in Python - Mini Project: Build & Apply

Multiple Return Values in Python

📖 Scenario: You are building a simple program to calculate the area and perimeter of a rectangle. This is useful in many real-life situations like planning a garden or a room.

🎯 Goal: Create a function that returns both the area and perimeter of a rectangle. Then use these values to display the results.

📋 What You'll Learn

Create a function that takes two parameters: length and width

The function should return two values: area and perimeter

Call the function with specific length and width values

Print the returned area and perimeter values

💡 Why This Matters

🌍 Real World

Calculating area and perimeter is common in construction, gardening, and interior design.

💼 Career

Understanding how to return multiple values from functions helps in writing clear and efficient code in many programming jobs.

1

Create variables for length and width

Create two variables called length and width and set them to 5 and 3 respectively.

Python

# Your code here

Hint

Think of length and width as the sides of a rectangle.

2

Define a function to calculate area and perimeter

Define a function called calculate_rectangle that takes two parameters: length and width. Inside the function, calculate the area as length * width and the perimeter as 2 * (length + width). Return both area and perimeter.

Python

length = 5
width = 3
# Your code here

Hint

Use the return statement to send back both values separated by a comma.

3

Call the function and store returned values

Call the function calculate_rectangle with the variables length and width. Store the returned values in two variables called area and perimeter.

Python

length = 5
width = 3
def calculate_rectangle(length, width):
    area = length * width
    perimeter = 2 * (length + width)
    return area, perimeter
# Your code here

Hint

Use two variables on the left side to receive the two returned values.

4

Print the area and perimeter

Print the values of area and perimeter using two separate print statements.

Python

length = 5
width = 3
def calculate_rectangle(length, width):
    area = length * width
    perimeter = 2 * (length + width)
    return area, perimeter

area, perimeter = calculate_rectangle(length, width)
# Your code here

Hint

Use print(area) and print(perimeter) to show the results.

Practice

1.

What does a Python function return when it has multiple values separated by commas in the return statement?

easy

A. A tuple containing all the returned values

B. A list containing all the returned values

C. Only the first value is returned

D. A dictionary with values as keys

Solution

1. Step 1: Understand Python return behavior

   When multiple values are separated by commas in a return statement, Python groups them into a tuple automatically.

2. Step 2: Identify the returned data type

   The returned object is a tuple containing all the values, not a list or dictionary.

3. Final Answer:

   A tuple containing all the returned values -> Option A

4. Quick Check:

   Multiple values returned = tuple [OK]

Hint: Multiple returns become a tuple automatically [OK]

Common Mistakes:

• Thinking it returns a list
• Assuming only one value is returned
• Confusing tuple with dictionary

2.

Which of the following is the correct syntax to return multiple values a and b from a function?

easy

A. return a, b

B. return {a: b}

C. return [a, b]

D. return {a, b}

Solution

1. Step 1: Review return syntax for multiple values

   Python allows returning multiple values separated by commas without parentheses.

2. Step 2: Compare options

   return a, b is correct and returns a tuple. return {a: b} returns a dictionary, return [a, b] returns a list, and return {a, b} returns a set, which are not typical for multiple return values.

3. Final Answer:

   return a, b -> Option A

4. Quick Check:

   Comma-separated values return tuple [OK]

Hint: Use commas without brackets to return multiple values [OK]

Common Mistakes:

• Using brackets unnecessarily
• Returning list or set instead of tuple
• Syntax errors with braces

3.

What will be the output of this code?

def get_values():
    return 5, 10

x, y = get_values()
print(x + y)

medium

A. 510

B. TypeError

C. 15

D. None

Solution

1. Step 1: Understand function return and unpacking

   The function returns two values 5 and 10 as a tuple. Variables x and y capture these values separately.

2. Step 2: Calculate the sum

   Adding x and y means 5 + 10 which equals 15.

3. Final Answer:

   15 -> Option C

4. Quick Check:

   5 + 10 = 15 [OK]

Hint: Unpack returned tuple into variables to use values [OK]

Common Mistakes:

• Concatenating numbers as strings
• Forgetting to unpack tuple
• Expecting a list instead of tuple

4.

Find the error in this code snippet:

def split_name(full_name):
    first, last = full_name.split()
    return first, last

f, l, m = split_name('John Doe')

medium

A. Missing return statement

B. Too many variables to unpack returned values

C. Function split_name returns a list, not tuple

D. split() method does not work on strings

Solution

1. Step 1: Analyze returned values and unpacking

   The function returns two values: first and last name. The caller tries to unpack into three variables.

2. Step 2: Identify mismatch in unpacking

   Trying to assign two returned values to three variables causes a ValueError due to too many variables to unpack.

3. Final Answer:

   Too many variables to unpack returned values -> Option B

4. Quick Check:

   Returned 2 values but unpacked into 3 variables [OK]

Hint: Match number of variables to returned values [OK]

Common Mistakes:

• Unpacking into more variables than returned
• Assuming split returns tuple always
• Ignoring ValueError messages

5.

Given this function that returns multiple values, how can you modify it to return the sum and product of a list of numbers?

def calculate(numbers):
    # Your code here

result = calculate([1, 2, 3, 4])
print(result)

Choose the correct implementation to return both sum and product.

hard

A. def calculate(numbers):
total = sum(numbers)
product = 0
for n in numbers:
product += n
return total, product

B. def calculate(numbers):
return sum(numbers) + product(numbers)

C. def calculate(numbers):
return [sum(numbers), product(numbers)]

D. def calculate(numbers):
total = sum(numbers)
product = 1
for n in numbers:
product *= n
return total, product

Solution

1. Step 1: Calculate sum and product correctly

   Sum is calculated using built-in sum(). Product requires initializing to 1 and multiplying each number.

2. Step 2: Return both values as multiple return values

   Return total and product separated by comma to return a tuple.

3. Final Answer:

   def calculate(numbers): total = sum(numbers) product = 1 for n in numbers: product *= n return total, product -> Option D

4. Quick Check:

   Return sum and product as tuple [OK]

Hint: Return sum and product separated by comma [OK]

Common Mistakes:

• Using product = 0 and adding instead of multiplying
• Trying to add sum and product instead of returning both
• Returning list instead of tuple