firestar5683
73 lines
2.1 KiB
Python
73 lines
2.1 KiB
Python
from typing import Callable, Optional, TypeVar, cast
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from reactivex import Observable, abc, compose
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from reactivex import operators as ops
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from reactivex import typing
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from reactivex.internal.basic import identity
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from reactivex.internal.utils import infinite
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from reactivex.typing import Mapper, MapperIndexed
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_T1 = TypeVar("_T1")
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_T2 = TypeVar("_T2")
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def map_(
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mapper: Optional[Mapper[_T1, _T2]] = None
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) -> Callable[[Observable[_T1]], Observable[_T2]]:
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_mapper = mapper or cast(Mapper[_T1, _T2], identity)
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def map(source: Observable[_T1]) -> Observable[_T2]:
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"""Partially applied map operator.
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Project each element of an observable sequence into a new form
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by incorporating the element's index.
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Example:
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>>> map(source)
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Args:
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source: The observable source to transform.
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Returns:
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Returns an observable sequence whose elements are the
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result of invoking the transform function on each element
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of the source.
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"""
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def subscribe(
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obv: abc.ObserverBase[_T2], scheduler: Optional[abc.SchedulerBase] = None
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) -> abc.DisposableBase:
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def on_next(value: _T1) -> None:
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try:
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result = _mapper(value)
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except Exception as err: # pylint: disable=broad-except
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obv.on_error(err)
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else:
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obv.on_next(result)
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return source.subscribe(
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on_next, obv.on_error, obv.on_completed, scheduler=scheduler
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)
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return Observable(subscribe)
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return map
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def map_indexed_(
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mapper_indexed: Optional[MapperIndexed[_T1, _T2]] = None
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) -> Callable[[Observable[_T1]], Observable[_T2]]:
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def _identity(value: _T1, _: int) -> _T2:
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return cast(_T2, value)
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_mapper_indexed = mapper_indexed or cast(typing.MapperIndexed[_T1, _T2], _identity)
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return compose(
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ops.zip_with_iterable(infinite()),
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ops.starmap_indexed(_mapper_indexed),
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)
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__all__ = ["map_", "map_indexed_"]
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