PythonAdvanced

Generators

Python generators and iterators: yield values lazily, build memory-efficient sequences, and use next to control iteration.

01Generator function

main.py

def count_up(n):
    for i in range(1, n + 1):
        yield i

for num in count_up(3):
    print(num)

Output

1
2
3

main.py

def fib(n):
    a, b = 0, 1
    for _ in range(n):
        yield a
        a, b = b, a + b

print(list(fib(7)))

Output

[0, 1, 1, 2, 3, 5, 8]

main.py

def gen():
    yield "a"
    yield "b"

g = gen()
print(next(g))
print(next(g))

Output

a
b

main.py

def naturals():
    n = 1
    while True:
        yield n
        n += 1

g = naturals()
print([next(g) for _ in range(5)])

Output

[1, 2, 3, 4, 5]