Generators and Yield
Produce values lazily without storing entire datasets in memory.
Learning objectives
- Differentiate between iterables, iterators, and generators
- Create memory-efficient generator functions using yield
Lesson material
Yield vs Return
Functions with yield return a generator object that evaluates values on demand when iterated.
Example code
def countdown(n):
while n > 0:
yield n
n -= 1
gen = countdown(3)
for num in gen:
print(num, end=" ")
print()Practice exercise: Fibonacci Generator
Write a generator function `fib(n)` yielding the first `n` numbers of Fibonacci sequence (starting 0, 1). Print all items generated for `fib(5)`.
Test yourself with the Module 12: Iterators & Generators quiz →