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Fibonacci Generator

Intermediate · Write the code · from 50 Python Practice Problems with Instant Answer Checking (Beginner to Advanced)

From the lesson: 50 Python Practice Problems with Instant Answer Checking (Beginner to Advanced)

Fifty problems, each with a code editor and real tests. Write your solution, press Check, and see exactly which cases pass. Stuck? Hints reveal one at a time, and the solution unlocks once you have checked at least once. Your code and progress are saved in this browser.

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Write a generator fibonacci() that yields the Fibonacci numbers forever: 0, 1, 1, 2, 3, 5, ... The tests take as many as they need with itertools.islice.

def fibonacci():
# use yield
pass
Solution unlocks after your first Check

What Check runs

Your code runs first, then each of these lines. The output must match exactly.

RunsExpected output
from itertools import islice print(list(islice(fibonacci(), 10)))[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
import types print(isinstance(fibonacci(), types.GeneratorType))True

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