Coroutines in Python: best practices

Question

I am wondering what is best for writing coroutines in Python 3. I develop basic methods that should accept some input (using the .send () method), perform calculations on this input, and then output the output.

The first approach I found is to do the following:

def coroutine(func):
  data = yield
  while 1:
    data = yield func(data)

It seems to work, but the line in the loop bends my mind. It looks like it first gives a function, and then takes input and executes the assignment after resuming. This is completely unintuitive for me.

Another approach that I am considering is:

def coroutine():
  while 1:
    data = yield
    [ do stuff with data here ... ]
    yield result

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Answer 1

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def coroutine():
  data = yield
  while True:
    print("I am doing stuff with data now")
    data = data * 2
    data = yield data

:

>>> co = coroutine()
>>> next(co)
>>> co.send(1)
I am doing stuff with data now
2
>>> co.send(88)
I am doing stuff with data now
176

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