Parameters and arguments in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of function with default and keyword arguments

What is the output of this Python code?

Python

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

print(greet("Alice"))
print(greet("Bob", greeting="Hi"))

A TypeError: greet() missing 1 required positional argument: 'greeting'

B Hello, Alice!\nHello, Bob!

C Hi, Alice!\nHi, Bob!

D Hello, Alice!\nHi, Bob!

💡 Hint

Remember the default value is used if no argument is given for that parameter.

The function greet has a default value for greeting. When called with only one argument, greeting uses its default 'Hello'. When called with greeting='Hi', it uses the provided value.

❓ Predict Output

intermediate

Output with *args and **kwargs parameters

What will this code print?

Python

def show_args(*args, **kwargs):
    print(f"Positional: {args}")
    print(f"Keyword: {kwargs}")

show_args(1, 2, a=3, b=4)

A Positional: [1, 2]\nKeyword: {'a': 3, 'b': 4}

B Positional: (1, 2)\nKeyword: {'a': 3, 'b': 4}

C Positional: (1, 2)\nKeyword: [('a', 3), ('b', 4)]

D TypeError: show_args() got multiple values for argument 'a'

💡 Hint

*args collects positional arguments as a tuple, **kwargs collects keyword arguments as a dictionary.

The *args parameter collects all positional arguments into a tuple. The **kwargs parameter collects all keyword arguments into a dictionary.

❓ Predict Output

advanced

Output of function with mutable default argument

What is the output of this code?

Python

def add_item(item, item_list=[]):
    item_list.append(item)
    return item_list

print(add_item('apple'))
print(add_item('banana'))

A ['apple']\n['banana']

B ['apple']\n['apple']

C ['apple']\n['apple', 'banana']

D TypeError: unhashable type: 'list'

💡 Hint

Default arguments are evaluated once when the function is defined, not each time it is called.

The default list is shared across calls, so the second call appends 'banana' to the same list that already contains 'apple'.

❓ Predict Output

advanced

Output of function with positional-only and keyword-only parameters

What will this code print?

Python

def func(a, /, b, *, c):
    return a + b + c

print(func(1, 2, c=3))

A 6

B TypeError: func() missing 1 required keyword-only argument: 'c'

C TypeError: func() got some positional-only arguments passed as keyword arguments

D TypeError: func() missing 1 required positional argument: 'b'

💡 Hint

Parameters before / are positional-only, parameters after * are keyword-only.

Parameter 'a' is positional-only, so it must be passed positionally. 'b' is positional or keyword, 'c' is keyword-only. The call matches these rules.

🧠 Conceptual

expert

Identify the error in function call with argument unpacking

Given the function definition below, which option will cause a TypeError when called?

Python

def combine(a, b, c):
    return a + b + c

A

kwargs = {'a': 1, 'b': 2, 'c': 3}
combine(**kwargs, c=4)

B

args = (1, 2, 3)
combine(*args)

C

kwargs = {'a': 1, 'b': 2}
combine(**kwargs, c=3)

D

args = (1, 2)
combine(*args, 3)

💡 Hint

Check if any argument is passed twice due to unpacking and explicit argument.

Option A passes 'c' twice: once in kwargs and once explicitly, causing TypeError: multiple values for argument 'c'.