Iterator & Generator

Iterator

• For implementing iterator, it is needed to implement _iter_ and _next_ method

• _iter_ return the class instance

• _next_ for handling ther next iter and when to stop

class AsyncIterator():
    # constructor, define some state
    def __init__(self):
        self.counter = 0
 
    # create an instance of the iterator
    def __aiter__(self):
        return self
 
    # return the next awaitable
    async def __anext__(self):
        # check for no further items
        if self.counter >= 10:
            raise StopAsyncIteration
        # increment the counter
        self.counter += 1
        # return the counter value
        return self.counter

async def test():
    it = AsyncIterator()
    async for result in it:
	    print(result)

await test()

/** 
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**/

Generator

• Similar with Generator, but using yield

class AsyncIterator():
    # constructor, define some state
    def __init__(self):
        self.counter = 0
 
    # create an instance of the iterator
    def __aiter__(self):
        return self
 
    # return the next awaitable
    async def __anext__(self):
        # check for no further items
        if self.counter >= 10:
            raise StopAsyncIteration
        # increment the counter
        self.counter += 1
        # return the counter value
        return self.counter

async def test():
    it = AsyncIterator()
    async for result in it:
	    print(result)

await test()
/**
 start 
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 end
**/

Ice_story/src/python/Asyncio/Asyncio_15.md at main · Jwindler/Ice_storyGitHub

帶你搞懂 Python 的 Iterable, Iterator 與 GeneratorMyApollo