Argument order rules in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of function call with mixed arguments

What is the output of this Python code?

Python

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

print(greet("Alice", punctuation="."))

A TypeError: positional argument follows keyword argument

B Hello, Alice!

C Hello, Alice.

D Hello, punctuation=., Alice

💡 Hint

Remember that positional arguments come before keyword arguments.

The function call uses a positional argument for 'name' and a keyword argument for 'punctuation'. The default greeting 'Hello' is used. So the output is 'Hello, Alice.'.

❓ Predict Output

intermediate

Error from wrong argument order

What error does this code produce?

Python

def add(x, y=5, z):
    return x + y + z

add(1, 2, 3)

A 6

B NameError: name 'z' is not defined

C SyntaxError: invalid syntax

D SyntaxError: non-default argument follows default argument

💡 Hint

Check the order of parameters with and without default values.

In Python, parameters with default values must come after parameters without defaults. Here, 'z' has no default but comes after 'y' which has a default, causing a SyntaxError.

❓ Predict Output

advanced

Output with *args and keyword-only arguments

What is the output of this code?

Python

def func(a, b, *args, c=10, d=20):
    return a + b + sum(args) + c + d

print(func(1, 2, 3, 4, c=5))

A 35

B 40

C TypeError: func() missing 1 required keyword-only argument: 'd'

D 30

💡 Hint

Remember that after *args, parameters are keyword-only.

Arguments: a=1, b=2, args=(3,4), c=5 (keyword), d=20 (default). Sum is 1+2+3+4+5+20=35.

❓ Predict Output

advanced

Output with positional-only and keyword-only arguments

What is the output of this code?

Python

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

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

A 6

B TypeError: example() missing 1 required positional argument: 'b'

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

D 5

💡 Hint

Positional-only arguments must be passed positionally, keyword-only must be passed by name.

a=1 (positional-only), b=2 (positional or keyword), c=3 (keyword-only). Sum is 1+2+3=6.

🧠 Conceptual

expert

Identify the invalid function definition

Which of these function definitions is invalid due to argument order rules?

A def f(a, b=2, *, c, d=4): pass

B def f(a=1, b, c=3): pass

C def f(a, /, b, *, c=3): pass

D def f(*args, b, c=3): pass

💡 Hint

Parameters with default values must come after those without defaults.

Option B has a parameter 'a' with default before 'b' without default, which is invalid syntax in Python.