Why doesn't my generator function produce correct values?

Question

I had an assignment for my programming class to write a generator function that takes an int ( n ) and a generator ( gen ) as arguments and generates the first n elements of the given generator. I wrote:

from typing import Iterator, Any

def basic_generator(n):  # Just a generator function to be able to test it out
    while True:
        yield n
        n += 1

def tryout(n: int, gen: Iterator[Any]) -> Iterator[Any]:
    i = 0
    while i < n:
        next(gen)
        yield i
        i = i + 1

In the feedback I received it told me it's wrong but it didn't say why. I get that it doesn't work but I don't understand why. Could someone please explain it to me?

Answer 1

You are yield ing the counter instead of the value ... Change to yield next(gen) .

It would also be cleaner to use a for loop instead of a while :

def tryout(n: int, gen: Iterator[Any]) -> Iterator[Any]:
    for _ in range(n):
        yield next(gen)