yield — Expert Examples

def running_average():
    total = 0
    count = 0
    average = None
    while True:
        value = yield average
        if value is None:
            break
        total += value
        count += 1
        average = total / count

# Drive the coroutine
gen = running_average()
next(gen)  # Prime the generator

for v in [10, 20, 30, 40, 50]:
    avg = gen.send(v)
    print(f"Added {v}, running average: {avg}")

# Generator state inspection
import inspect
def simple():
    yield 1
    yield 2

g = simple()
print(f"\nState: {inspect.getgeneratorstate(g)}")
next(g)
print(f"State: {inspect.getgeneratorstate(g)}")
list(g)
print(f"State: {inspect.getgeneratorstate(g)}")