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https://github.com/firestar5683/StarPilot.git
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firestar5683
92 lines
2.4 KiB
Python
92 lines
2.4 KiB
Python
from typing import Callable, List, Optional, TypeVar, cast
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from reactivex import Observable, abc, typing
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from reactivex.internal.basic import default_sub_comparer
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_T = TypeVar("_T")
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_TKey = TypeVar("_TKey")
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def extrema_by(
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source: Observable[_T],
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key_mapper: typing.Mapper[_T, _TKey],
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comparer: typing.SubComparer[_TKey],
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) -> Observable[List[_T]]:
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def subscribe(
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observer: abc.ObserverBase[List[_T]],
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scheduler: Optional[abc.SchedulerBase] = None,
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) -> abc.DisposableBase:
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has_value = False
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last_key: _TKey = cast(_TKey, None)
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items: List[_T] = []
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def on_next(x: _T) -> None:
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nonlocal has_value, last_key
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try:
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key = key_mapper(x)
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except Exception as ex:
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observer.on_error(ex)
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return
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comparison = 0
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if not has_value:
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has_value = True
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last_key = key
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else:
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try:
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comparison = comparer(key, last_key)
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except Exception as ex1:
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observer.on_error(ex1)
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return
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if comparison > 0:
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last_key = key
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items[:] = []
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if comparison >= 0:
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items.append(x)
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def on_completed():
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observer.on_next(items)
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observer.on_completed()
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return source.subscribe(
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on_next, observer.on_error, on_completed, scheduler=scheduler
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)
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return Observable(subscribe)
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def min_by_(
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key_mapper: typing.Mapper[_T, _TKey],
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comparer: Optional[typing.SubComparer[_TKey]] = None,
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) -> Callable[[Observable[_T]], Observable[List[_T]]]:
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"""The `min_by` operator.
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Returns the elements in an observable sequence with the minimum key
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value according to the specified comparer.
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Examples:
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>>> res = min_by(lambda x: x.value)
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>>> res = min_by(lambda x: x.value, lambda x, y: x - y)
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Args:
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key_mapper: Key mapper function.
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comparer: [Optional] Comparer used to compare key values.
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Returns:
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An observable sequence containing a list of zero or more
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elements that have a minimum key value.
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"""
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cmp = comparer or default_sub_comparer
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def min_by(source: Observable[_T]) -> Observable[List[_T]]:
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return extrema_by(source, key_mapper, lambda x, y: -cmp(x, y))
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return min_by
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__all__ = ["min_by_"]
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