seq.py - functional - Tailord/omd

from typing import TypeVar, Sequence, Callable, Self
from itertools import islice

T = TypeVar('T')
U = TypeVar('U')


class Seq:
    def __init__(self, sequence: Sequence[T]) -> None:
        self._seq = sequence

    def map(self, func: Callable[[T], U]) -> Self:
        self._seq = map(func, self._seq)
        return self

    def filter(self, func: Callable[[T], bool]) -> Self:
        self._seq = filter(func, self._seq)
        return self

    def take(self, cnt: int) -> list[U]:
        return list(islice(self._seq, cnt))


if __name__ == '__main__':
    numbers = [1, 2, 3, 4, 5]
    seq = Seq(numbers)
    res = seq.filter(lambda n: n % 2 == 0).map(lambda n: n + 10).take(3)
    assert res == [12, 14]