Why different argument types are needed in Python - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a function that takes one argument and prints it.

Python

def greet([1]):
    print(f"Hello, {name}!")
greet("Alice")

Drag options to blanks, or click blank then click option'

Aname

Bvalue

Cmsg

Dinput

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different parameter name than the one used inside the function causes a NameError.

The function parameter should be named 'name' because the print statement uses 'name'.

2fill in blank

medium

Complete the code to define a function that adds two numbers and returns the result.

Python

def add_numbers(a, [1]):
    return a + b

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

Drag options to blanks, or click blank then click option'

Ac

Bx

Cnum

Db

Attempts:

3 left

💡 Hint

Common Mistakes

Using a parameter name that does not match the variable in the return statement causes a NameError.

The second parameter must be named 'b' because the return statement uses 'b'.

3fill in blank

hard

Fix the error in the function call by completing the argument type correctly.

Python

def repeat_text(text, times):
    return text * times

result = repeat_text("Hi", [1])
print(result)

Drag options to blanks, or click blank then click option'

A"3"

Btimes

C3

D'3'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the number as a string causes the function to repeat the string incorrectly or raise an error.

The second argument must be an integer (3) to multiply the string correctly.

4fill in blank

hard

Fill both blanks to create a function that filters numbers greater than 5 from a list.

Python

def filter_numbers(numbers):
    return [num for num in numbers if num [1] [2]]

result = filter_numbers([2, 7, 4, 9])
print(result)

Drag options to blanks, or click blank then click option'

A>

B5

C<

D7

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' will filter numbers less than 5.

Using the wrong number in the comparison changes the filter result.

The condition 'num > 5' filters numbers greater than 5.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps words to their lengths if length is greater than 3.

Python

words = ["apple", "cat", "banana", "dog"]
lengths = { [1]: [2] for word in words if len(word) [3] 3 }
print(lengths)

Drag options to blanks, or click blank then click option'

Aword

Blen(word)

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' changes the filter condition.

Swapping key and value causes incorrect dictionary structure.

The dictionary comprehension maps each word to its length if the length is greater than 3.

Practice

1. Why do Python functions use different types of arguments like positional, default, *args, and **kwargs?

easy

A. To make the code run faster by limiting inputs

B. To allow functions to accept varying numbers and types of inputs flexibly

C. To force users to always provide all arguments

D. To prevent functions from being reused

Solution

1. Step 1: Understand argument types purpose

   Different argument types let functions accept inputs in flexible ways, like fixed, optional, or many arguments.

2. Step 2: Match flexibility with function use

   This flexibility helps reuse functions with different input needs without errors or extra code.

3. Final Answer:

   To allow functions to accept varying numbers and types of inputs flexibly -> Option B

4. Quick Check:

   Argument flexibility = To allow functions to accept varying numbers and types of inputs flexibly [OK]

Hint: Think: flexibility in inputs means different argument types [OK]

Common Mistakes:

• Thinking all arguments must always be provided
• Confusing argument types with performance improvements
• Believing argument types limit function reuse

2. Which of the following is the correct syntax to define a function that accepts any number of positional arguments?

easy

A. def func(**args):

B. def func(args*):

C. def func(args):

D. def func(*args):

Solution

1. Step 1: Recall syntax for variable positional arguments

   In Python, *args collects any number of positional arguments into a tuple.

2. Step 2: Identify correct syntax

   Only 'def func(*args):' correctly uses the * before args to accept multiple positional arguments.

3. Final Answer:

   def func(*args): -> Option D

4. Quick Check:

   *args syntax = def func(*args): [OK]

Hint: Remember *args collects extra positional arguments [OK]

Common Mistakes:

• Placing * after the argument name
• Using **args for positional arguments
• Omitting the * for variable arguments

3. What will be the output of this code?

def greet(name, greeting='Hello'):
    print(f"{greeting}, {name}!")

greet('Alice')
greet('Bob', 'Hi')

medium

A. Hello, Alice!\nHi, Bob!

B. Hello, Alice!\nHello, Bob!

C. Hi, Alice!\nHi, Bob!

D. Error because greeting is missing

Solution

1. Step 1: Understand default argument behavior

   The function greet has a default greeting 'Hello'. If no greeting is given, it uses 'Hello'.

2. Step 2: Trace function calls

   First call: greet('Alice') uses default greeting 'Hello'. Second call: greet('Bob', 'Hi') uses provided greeting 'Hi'.

3. Final Answer:

   Hello, Alice!\nHi, Bob! -> Option A

4. Quick Check:

   Default argument used when missing = Hello, Alice!\nHi, Bob! [OK]

Hint: Default arguments fill in missing values automatically [OK]

Common Mistakes:

• Assuming default arguments must always be provided
• Confusing positional and default argument order
• Expecting an error when default is missing

4. Identify the error in this function definition:

def add_numbers(a, b=5, *args, c):
    return a + b + sum(args) + c

medium

A. Cannot use *args and default arguments together

B. Missing return statement

C. Positional argument after *args without default is invalid

D. No error in the function definition

Solution

1. Step 1: Analyze argument order rules

   In Python, after *args, following arguments are keyword-only and can lack defaults (required keyword args). Defaults like b=5 before *args are allowed.

2. Step 2: Check argument 'c' position

   'c' is a required keyword-only argument after *args without a default value, which is valid syntax in Python 3. However, if the function is intended to be called without specifying 'c' as a keyword argument, it will cause a TypeError. The error is not in syntax but in usage.

3. Final Answer:

   Positional argument after *args without default is invalid -> Option C

4. Quick Check:

   Keyword-only arguments without default must be provided when calling the function [OK]

Hint: Arguments after *args are keyword-only and must be provided if no default [OK]

Common Mistakes:

• Ignoring keyword-only argument rules
• Thinking *args forbids any following arguments
• Assuming missing return causes syntax error

5. You want to write a function that accepts a fixed first argument, any number of extra positional arguments, and any number of keyword arguments. Which function header is correct?

hard

A. def func(first, *args, **kwargs):

B. def func(*args, first, **kwargs):

C. def func(**kwargs, *args, first):

D. def func(first, **kwargs, *args):

Solution

1. Step 1: Recall argument order in function definitions

   Python requires positional arguments first, then *args, then keyword-only arguments, then **kwargs last.

2. Step 2: Match correct order

   def func(first, *args, **kwargs): follows correct order: fixed argument 'first', then *args, then **kwargs.

3. Final Answer:

   def func(first, *args, **kwargs): -> Option A

4. Quick Check:

   Correct argument order = def func(first, *args, **kwargs): [OK]

Hint: Order: fixed, *args, then **kwargs in function header [OK]

Common Mistakes:

• Placing *args after **kwargs
• Putting keyword-only arguments before *args incorrectly
• Mixing order of *args and **kwargs