36 lines
970 B
Python
36 lines
970 B
Python
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import itertools
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from typing import Tuple, TypeVar, Iterable
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T = TypeVar('T')
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def groupby_index(iter: Iterable[T],n:int) -> Iterable[Iterable[T]]:
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"""group list by index
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Args:
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iter (Iterable[T]): iterator to group by index
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n (int): The size of groups
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Returns:
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Iterable[Iterable[T]]: iterable object to group by index
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>>> [*map(lambda x:[*x],groupby_index([1,2,3,4],2))]
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[[1, 2], [3, 4]]
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"""
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def keyfunc(x: Tuple[int,T]) -> int:
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k, _ = x
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return (k // n)
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def mapper(x: Tuple[int, Tuple[int, T]]):
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_, v = x
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return map(lambda y: y[1],v)
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g = itertools.groupby(enumerate(iter), keyfunc)
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return map(mapper,g)
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if __name__ == "__main__":
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test_list = [*range(20,-10,-1)]
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for g in groupby_index(test_list,4):
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print([*g])
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print("===")
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print([*map(lambda x:[*x],groupby_index([1,2,3,4],2))])
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for g in groupby_index([1,2,3,4],2):
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print([*g])
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