Keyword arguments in Python - Mini Project: Build & Apply

Using Keyword Arguments in Python Functions

📖 Scenario: You are creating a simple program to greet people with their name and age. You want to use keyword arguments in a function to make your code clear and flexible.

🎯 Goal: Build a Python function that uses keyword arguments to greet a person by their name and age. You will call this function with keyword arguments to see how it works.

📋 What You'll Learn

Create a function called greet that takes two keyword arguments: name and age.

Call the greet function using keyword arguments.

Print the greeting message inside the function.

💡 Why This Matters

🌍 Real World

Keyword arguments help make your code easier to read and maintain, especially when functions have many parameters.

💼 Career

Understanding keyword arguments is important for writing clear and bug-free code in many programming jobs.

1

Define the greet function with keyword arguments

Write a function called greet that takes two keyword arguments: name and age. Inside the function, create a variable message that stores the string: f"Hello, {name}! You are {age} years old."

Python

# Define the greet function with keyword arguments name and age
# Your code here

Hint

Use def greet(*, name, age): to force keyword arguments.

2

Add a print statement inside the greet function

Inside the greet function, add a line to print the message variable.

Python

def greet(*, name, age):
    message = f"Hello, {name}! You are {age} years old."
    # Print the message
    # Your code here

Hint

Use print(message) to show the greeting.

3

Call the greet function with keyword arguments

Call the greet function using keyword arguments: name="Alice" and age=30.

Python

def greet(*, name, age):
    message = f"Hello, {name}! You are {age} years old."
    print(message)

# Call greet with name='Alice' and age=30
# Your code here

Hint

Call the function like greet(name="Alice", age=30).

4

Call the greet function with keyword arguments in reverse order

Call the greet function again using keyword arguments but this time with age=25 and name="Bob". Then run the program to see both greetings printed.

Python

def greet(*, name, age):
    message = f"Hello, {name}! You are {age} years old."
    print(message)

greet(name="Alice", age=30)

# Call greet with age=25 and name='Bob'
# Your code here

Hint

Try calling greet(age=25, name="Bob") to see how keyword arguments allow any order.

Practice

1. What is the main advantage of using keyword arguments when calling a function in Python?

easy

A. Keyword arguments make the function run faster.

B. You must provide arguments in the exact order defined in the function.

C. You can specify arguments by name, making the code clearer.

D. They allow you to skip required arguments.

Solution

1. Step 1: Understand keyword arguments

   Keyword arguments let you name the inputs when calling a function, so you don't have to remember the order.

2. Step 2: Compare options

   You can specify arguments by name, making the code clearer. correctly states that naming arguments makes code clearer. Options B, C, and D are incorrect because keyword arguments do not require order, do not affect speed, and cannot skip required arguments.

3. Final Answer:

   You can specify arguments by name, making the code clearer. -> Option C

4. Quick Check:

   Keyword arguments = clearer code [OK]

Hint: Keyword arguments name inputs, so order doesn't matter [OK]

Common Mistakes:

• Thinking keyword arguments must follow positional order
• Believing keyword arguments speed up the function
• Assuming keyword arguments can skip required parameters

2. Which of the following is the correct way to call the function def greet(name, age): using keyword arguments?

easy

A. greet(name='Alice', age=30)

B. greet('Alice', 30)

C. greet(age=30, 'Alice')

D. greet(name=30, age='Alice')

Solution

1. Step 1: Check keyword argument syntax

   Keyword arguments require the format parameter=value. greet(name='Alice', age=30) uses name='Alice' and age=30, which is correct.

2. Step 2: Identify errors in other options

   greet('Alice', 30) uses positional arguments only, which is valid syntax but does not use keyword arguments. greet(age=30, 'Alice') places positional argument after keyword, which is invalid syntax. greet(name=30, age='Alice') swaps types incorrectly.

3. Final Answer:

   greet(name='Alice', age=30) -> Option A

4. Quick Check:

   Keyword args = parameter=value pairs [OK]

Hint: Use parameter=value pairs for keyword arguments [OK]

Common Mistakes:

• Placing positional arguments after keyword arguments
• Swapping argument names and values
• Mixing types incorrectly in keyword arguments

3. What will be the output of the following code?

def info(name, age):
    print(f"Name: {name}, Age: {age}")

info(age=25, name='Bob')

medium

A. Name: 25, Age: Bob

B. Name: Bob, Age: 25

C. Name: , Age:

D. TypeError

Solution

1. Step 1: Understand keyword argument order

   Keyword arguments allow passing arguments in any order by naming them explicitly.

2. Step 2: Match arguments to parameters

   Here, age=25 and name='Bob' are passed, so name gets 'Bob' and age gets 25.

3. Final Answer:

   Name: Bob, Age: 25 -> Option B

4. Quick Check:

   Keyword args reorder inputs correctly [OK]

Hint: Keyword arguments can be in any order [OK]

Common Mistakes:

• Assuming order matters with keyword arguments
• Confusing parameter names with values
• Expecting errors when order is changed

4. Identify the error in the following function call:

def multiply(x, y):
    return x * y

result = multiply(x=5, 10)

medium

A. SyntaxError: positional argument after keyword argument

B. TypeError: missing required positional argument

C. No error, result is 50

D. NameError: variable not defined

Solution

1. Step 1: Check argument order rules

   In Python, positional arguments cannot come after keyword arguments in a function call.

2. Step 2: Analyze the call

   The call multiply(x=5, 10) has a keyword argument first, then a positional argument, which causes a syntax error.

3. Final Answer:

   SyntaxError: positional argument after keyword argument -> Option A

4. Quick Check:

   Positional args must come before keyword args [OK]

Hint: Positional arguments must come before keyword arguments [OK]

Common Mistakes:

• Placing positional arguments after keyword arguments
• Confusing error types for this syntax
• Assuming this call runs without error

5. Given the function def order(item, quantity=1, price=10):, which call correctly orders 3 items with a price of 15 each using keyword arguments?

hard

A. order('apple', 3, 15)

B. order(price=15, quantity=3)

C. order(quantity=3, 'apple', price=15)

D. order(item='apple', price=15, quantity=3)

Solution

1. Step 1: Understand function parameters and defaults

   The function has one required parameter item and two optional parameters quantity and price with defaults.

2. Step 2: Check each call for correctness

   order('apple', 3, 15) uses positional arguments only, which is valid but not keyword arguments. order(item='apple', price=15, quantity=3) uses keyword arguments for all parameters, correctly naming them in any order. order(quantity=3, 'apple', price=15) places positional argument after keyword argument, which is invalid. order(price=15, quantity=3) misses the required item argument.

3. Final Answer:

   order(item='apple', price=15, quantity=3) -> Option D

4. Quick Check:

   Keyword args can be in any order, all required given [OK]

Hint: Use all required keywords, order doesn't matter [OK]

Common Mistakes:

• Omitting required arguments
• Placing positional after keyword arguments
• Using positional only when keyword is asked