68 lines
1.8 KiB
Python
68 lines
1.8 KiB
Python
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import collections
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import sys
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import typing
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try:
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from os import scandir
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except ImportError:
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from scandir import scandir
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# https://pypi.org/project/asyncio_utils/
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async def anext(iterator: typing.AsyncIterator[typing.Any], *args, **kwargs
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) -> typing.Any:
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"""Mimics the builtin ``next`` for an ``AsyncIterator``.
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:param iterator: An ``AsyncIterator`` to get the next value from.
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:param default: Can be supplied as second arg or as a kwarg. If a value is
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supplied in either of those positions then a
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``StopAsyncIteration`` will not be raised and the
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``default`` will be returned.
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:raises TypeError: If the input is not a :class:`collections.AsyncIterator`
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Example::
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>>> async def main():
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myrange = await arange(1, 5)
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for n in range(1, 5):
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print(n, n == await anext(myrange))
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try:
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n = await anext(myrange)
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print("This should not be shown")
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except StopAsyncIteration:
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print('Sorry no more values!')
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>>> loop.run_until_complete(main())
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1 True
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2 True
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3 True
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4 True
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Sorry no more values!
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"""
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if not isinstance(iterator, collections.AsyncIterator):
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raise TypeError(f'Not an AsyncIterator: {iterator}')
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use_default = False
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default = None
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if len(args) > 0:
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default = args[0]
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use_default = True
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else:
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if 'default' in kwargs:
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default = kwargs['default']
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use_default = True
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try:
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return await iterator.__anext__()
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except StopAsyncIteration:
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if use_default:
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return default
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raise StopAsyncIteration
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