61 lines
1.2 KiB
Python
61 lines
1.2 KiB
Python
"""
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A coroutine to compute a running average.
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Testing ``averager`` by itself::
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# BEGIN RETURNING_AVERAGER_DEMO1
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>>> coro_avg = averager()
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>>> next(coro_avg) # <1>
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>>> coro_avg.send(10)
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>>> coro_avg.send(30)
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>>> coro_avg.send(6.5)
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>>> coro_avg.send(None) # <2>
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Traceback (most recent call last):
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...
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StopIteration: Result(count=3, average=15.5)
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# END RETURNING_AVERAGER_DEMO1
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Catching `StopIteration` to extract the value returned by
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the coroutine::
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# BEGIN RETURNING_AVERAGER_DEMO2
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>>> coro_avg = averager()
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>>> next(coro_avg)
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>>> coro_avg.send(10)
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>>> coro_avg.send(30)
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>>> coro_avg.send(6.5)
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>>> try:
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... coro_avg.send(None)
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... except StopIteration as exc:
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... result = exc.value
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...
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>>> result
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Result(count=3, average=15.5)
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# END RETURNING_AVERAGER_DEMO2
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"""
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# BEGIN RETURNING_AVERAGER
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from collections import namedtuple
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Result = namedtuple('Result', 'count average')
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def averager():
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total = 0.0
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count = 0
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average = None
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while True:
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term = yield
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if term is None:
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break # <1>
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total += term
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count += 1
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average = total/count
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return Result(count, average) # <2>
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# END RETURNING_AVERAGER |