Python Type Hints Exercises With Answers

What does name: str mean in a function signature?

1. Name is optional
2. Name is converted to a string
3. Name must be a class
4. Name is expected to be a stringcorrect

Answer: Name is expected to be a string

Why: The annotation documents the expected type; it does not convert the value.

What does -> int describe?

1. The first parameter
2. A runtime check
3. A required import
4. The return typecorrect

Answer: The return type

Why: The arrow introduces the function's return annotation.

What does list[int] mean?

1. An integer that is also a list
2. A list of exactly one item
3. A list whose items are integerscorrect
4. A list with one integer

Answer: A list whose items are integers

Why: The type inside the brackets describes each element.

What does float | None mean?

1. The function returns two floats
2. The value is always zero
3. The value must be a tuple
4. The value may be a float or Nonecorrect

Answer: The value may be a float or None

Why: The union lists both possible kinds of value.

Complete the parameter annotation.

def greet(name: ____) -> str:
    return f"Hello, {name}"

Answer: str

Why: The name should be a string.

Complete the list element type.

def total(values: list[____]) -> int:
    return sum(values)

Answer: int

Why: values contains integers.

Complete the union operator.

def find_price(item: str) -> float ____ None:
    return None

Answer: |

Why: A vertical bar combines float and None.

Complete the return annotation arrow.

def double(n: int) ____ int:
    return n * 2

Answer: ->

Why: The arrow separates the parameter list from the return type.

What appears on the screen?

def f(n: int) -> int:
    return n + 1
print(f(2))

Answer: 3

Why: The hint describes the value, and the function still returns three.

What is printed?

def f(x: str = "a") -> str:
    return x * 2
print(f())

Answer: aa

Why: The default is a, and a repeated twice is aa.

What is the output?

def f(x: int | None) -> str:
    return "none" if x is None else str(x)
print(f(None))

Answer: none

Why: None takes the first branch and returns the string none.

What does this code print?

from typing import get_type_hints
def f(n: int) -> str:
    return str(n)
print(get_type_hints(f)["n"].__name__)

Answer: int

Why: get_type_hints reads the annotation, whose type object is named int.