Python Functions and Scope 4

Question 1

What does the `functools.wraps` decorator do?

Accepted Answer

Copies the wrapped function's metadata to the wrapper function

Answer

`functools.wraps` copies attributes like `__name__` and `__doc__` from the wrapped function to the decorator wrapper, preserving introspection.

Question 2

What is the output of: `f = lambda x, y=2: x * y; print(f(3))`?

Accepted Answer

6

Answer

`y` defaults to 2, so `f(3)` computes `3 * 2 = 6`.

Question 3

Which built-in function applies a function to every item in an iterable?

Accepted Answer

map()

Answer

`map(func, iterable)` returns an iterator that applies `func` to each element of the iterable.

Question 4

When is a Python function's default argument value evaluated?

Accepted Answer

At function definition time

Answer

Default values are evaluated once when the `def` statement is executed, not on each call — this is why mutable defaults can cause bugs.

Question 5

What does `inspect.signature(func)` return?

Accepted Answer

A Signature object describing the function's parameters

Answer

`inspect.signature` returns a `Signature` object that contains information about the function's parameters and their defaults.

Python Practice Test