L5·Intermediate/Advanced

🌀Iterators & Generators

Lazy sequences you can walk once.

iternextyieldgenerator

An iterator has __iter__ returning self and __next__ raising StopIteration when done.

def with yield produces a generator function — each yield suspends state until next() resumes.

Delegates iteration to a sub-iterable — flattens nested generators.

Animated step-through

step 1 / 6// fib(10) creates a generator (no code runs yet)

1def fib(n):
2    a, b = 0, 1
3    for _ in range(n):
4        yield a
5        a, b = b, a + b
6
7print(list(fib(10)))

Variables

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Question 1 / 2

What does calling a generator function do?