ner-study/groupby_index.py

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2022-02-18 17:29:46 +09:00
import itertools
from typing import Tuple, TypeVar, Iterable
T = TypeVar('T')
def groupby_index(iter: Iterable[T],n:int) -> Iterable[Iterable[T]]:
"""group list by index
Args:
iter (Iterable[T]): iterator to group by index
n (int): The size of groups
Returns:
Iterable[Iterable[T]]: iterable object to group by index
>>> [*map(lambda x:[*x],groupby_index([1,2,3,4],2))]
[[1, 2], [3, 4]]
"""
def keyfunc(x: Tuple[int,T]) -> int:
k, _ = x
return (k // n)
def mapper(x: Tuple[int, Tuple[int, T]]):
_, v = x
return map(lambda y: y[1],v)
g = itertools.groupby(enumerate(iter), keyfunc)
return map(mapper,g)
if __name__ == "__main__":
test_list = [*range(20,-10,-1)]
for g in groupby_index(test_list,4):
print([*g])
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print("===")
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print([*map(lambda x:[*x],groupby_index([1,2,3,4],2))])
for g in groupby_index([1,2,3,4],2):
print([*g])