Multiple parameters in Python - Mini Project: Build & Apply

Using Multiple Parameters in Functions

📖 Scenario: Imagine you are creating a simple calculator that can add two numbers. You want to write a function that takes two numbers as input and returns their sum.

🎯 Goal: Build a function called add_numbers that takes two parameters and returns their sum. Then call this function with specific numbers and print the result.

📋 What You'll Learn

Create a function named add_numbers with two parameters: num1 and num2

Inside the function, return the sum of num1 and num2

Call the function add_numbers with the numbers 5 and 7

Print the result of the function call

💡 Why This Matters

🌍 Real World

Functions with multiple parameters are used everywhere, like calculating totals, processing user input, or controlling devices.

💼 Career

Understanding how to write and use functions with multiple parameters is a key skill for any programming job, enabling you to write reusable and clear code.

1

Define the function with two parameters

Write a function called add_numbers that takes two parameters named num1 and num2. Inside the function, return the sum of num1 and num2.

Python

# Define the function add_numbers with parameters num1 and num2
# Your code here

Hint

Use the def keyword to create a function. The parameters go inside the parentheses.

2

Call the function with two numbers

Call the function add_numbers with the numbers 5 and 7 and store the result in a variable called result.

Python

def add_numbers(num1, num2):
    return num1 + num2

# Call add_numbers with 5 and 7 and store in result
# Your code here

Hint

Use the function name followed by parentheses with the two numbers inside.

3

Print the result

Write a print statement to display the value stored in the variable result.

Python

def add_numbers(num1, num2):
    return num1 + num2

result = add_numbers(5, 7)

# Print the result
# Your code here

Hint

Use the print function with the variable name inside the parentheses.

4

Test with different numbers

Call the function add_numbers again with the numbers 10 and 20 and print the result directly without storing it in a variable.

Python

def add_numbers(num1, num2):
    return num1 + num2

result = add_numbers(5, 7)
print(result)

# Call add_numbers with 10 and 20 and print the result directly
# Your code here

Hint

Call the function inside the print function directly.

Practice

1. What does it mean when a Python function has multiple parameters?
def greet(name, age):

easy

A. The function can only have one parameter at a time.

B. The function can only return multiple values.

C. The function must be called without any arguments.

D. The function can receive more than one piece of information to work with.

Solution

1. Step 1: Understand function parameters

   Parameters inside parentheses let a function accept inputs to use inside its code.

2. Step 2: Multiple parameters mean multiple inputs

   When separated by commas, each parameter is a separate input the function expects.

3. Final Answer:

   The function can receive more than one piece of information to work with. -> Option D

4. Quick Check:

   Multiple parameters = multiple inputs [OK]

Hint: Multiple parameters mean multiple inputs separated by commas [OK]

Common Mistakes:

• Thinking parameters are outputs
• Believing functions can't have more than one parameter
• Confusing parameters with function return values

2. Which of the following is the correct way to define a function with two parameters named x and y?

easy

A. def add(x; y):

B. def add(x y):

C. def add(x, y):

D. def add[x, y]:

Solution

1. Step 1: Check function definition syntax

   Python functions use parentheses to list parameters separated by commas.

2. Step 2: Identify correct separator and brackets

   Parameters must be separated by commas inside parentheses, not spaces, semicolons, or brackets.

3. Final Answer:

   def add(x, y): -> Option C

4. Quick Check:

   Parameters separated by commas inside () [OK]

Hint: Use commas between parameters inside parentheses [OK]

Common Mistakes:

• Using spaces instead of commas
• Using semicolons or brackets instead of commas and parentheses
• Missing parentheses around parameters

3. What will be the output of this code?

def multiply(a, b):
    return a * b

result = multiply(3, 4)
print(result)

medium

A. 12

B. 7

C. 34

D. Error

Solution

1. Step 1: Understand function call with parameters

   The function multiply receives 3 and 4 as inputs for a and b.

2. Step 2: Calculate the return value

   It returns the product 3 * 4 = 12, which is stored in result and printed.

3. Final Answer:

   12 -> Option A

4. Quick Check:

   3 times 4 equals 12 [OK]

Hint: Multiply inputs given to function parameters [OK]

Common Mistakes:

• Adding instead of multiplying
• Concatenating numbers as strings
• Expecting an error due to parameters

4. Find the error in this function definition:

def greet(name, age)
    print(f"Hello {name}, you are {age} years old.")

medium

A. Missing colon at the end of the function header.

B. Parameters should be inside square brackets.

C. The print statement should be outside the function.

D. Function name cannot be 'greet'.

Solution

1. Step 1: Check function header syntax

   Python requires a colon ':' at the end of the function header line.

2. Step 2: Identify missing colon

   The given function header lacks the colon after the closing parenthesis.

3. Final Answer:

   Missing colon at the end of the function header. -> Option A

4. Quick Check:

   Function header must end with ':' [OK]

Hint: Always put ':' after function header parentheses [OK]

Common Mistakes:

• Forgetting the colon ':'
• Using wrong brackets for parameters
• Misplacing print statement

5. You want to write a function describe_person that takes name, age, and city as parameters and returns a sentence like:
"Alice is 30 years old and lives in Paris."
Which function definition and return statement is correct?

hard

A. def describe_person(name, age, city):
print(f"{name} is {age} years old and lives in {city}.")

B. def describe_person(name, age, city):
return f"{name} is {age} years old and lives in {city}."

C. def describe_person(name, age, city):
return name + " is " + age + " years old and lives in " + city + "."

D. def describe_person(name, age, city):
return f"{name} is {age} years old lives in {city}."

Solution

1. Step 1: Check function parameters and string formatting

   The function must accept three parameters and return a formatted string with all parts included.

2. Step 2: Compare return statements

   def describe_person(name, age, city): return f"{name} is {age} years old and lives in {city}." uses an f-string correctly with all parts and punctuation. def describe_person(name, age, city): return name + " is " + age + " years old and lives in " + city + "." tries string addition but age is an int, causing error. def describe_person(name, age, city): print(f"{name} is {age} years old and lives in {city}.") prints instead of returning. def describe_person(name, age, city): return f"{name} is {age} years old lives in {city}." misses 'and' in the sentence.

3. Final Answer:

   def describe_person(name, age, city): return f"{name} is {age} years old and lives in {city}." -> Option B

4. Quick Check:

   Use f-string with all parameters and return [OK]

Hint: Use f-string with all parameters and return the string [OK]

Common Mistakes:

• Concatenating strings with int without conversion
• Using print instead of return
• Missing words or punctuation in the string