Keyword arguments in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are keyword arguments in Python functions?

Keyword arguments are arguments passed to a function by explicitly naming each parameter and assigning it a value. This allows you to specify which argument corresponds to which parameter, regardless of their order.

beginner

How do keyword arguments improve function calls?

They make function calls clearer and easier to read by naming each argument. They also allow skipping some optional parameters and changing the order of arguments without confusion.

beginner

Example: What does this function call do?

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

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

This calls the greet function using keyword arguments. It prints: "Hello Alice, you are 30 years old." The order of arguments is switched but still works because keywords are used.

intermediate

Can you mix positional and keyword arguments in a function call?

Yes, but positional arguments must come first, followed by keyword arguments. For example: func(1, 2, c=3) is valid, but func(a=1, 2) is not.

intermediate

What happens if you pass the same argument both positionally and as a keyword?

Python raises a TypeError because the function receives multiple values for the same parameter, which causes confusion.

What is the main benefit of using keyword arguments in Python?

A They allow you to skip defining functions.

B They make the program run faster.

C They prevent any errors in the code.

D You can specify arguments in any order.

Keyword arguments let you specify arguments in any order by naming them explicitly.

Which of the following is a valid function call using keyword arguments?

A func(a=1, b=2)

B func(1, 2, 3)

C func(1, b=2, a=3)

D func(a=1, 2)

func(a=1, b=2) uses only keyword arguments and is valid. Option D is invalid because positional arguments cannot follow keyword arguments.

What error occurs if you pass the same argument twice, once positionally and once as a keyword?

A ValueError

B SyntaxError

C TypeError

D NameError

Python raises a TypeError when a parameter receives multiple values.

Can you omit some arguments when using keyword arguments if the function has default values?

A Only positional arguments can be skipped.

B Yes, keyword arguments let you skip optional parameters.

C No, all arguments must be provided.

D Only if the function has no parameters.

Keyword arguments allow skipping parameters that have default values.

Which of these is NOT true about keyword arguments?

A They must always come before positional arguments.

B They allow arguments to be passed in any order.

C They can be mixed with positional arguments if positional come first.

D They improve code readability.

Keyword arguments must come after positional arguments, not before.

Explain what keyword arguments are and why they are useful in Python functions.

Think about how naming arguments helps when calling functions.

Describe the rules for mixing positional and keyword arguments in a function call.

Consider the order and uniqueness of arguments.

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