from typing import Callable, List, Optional, TypeVar from reactivex import Observable, abc _T = TypeVar("_T") def skip_last_(count: int) -> Callable[[Observable[_T]], Observable[_T]]: def skip_last(source: Observable[_T]) -> Observable[_T]: """Bypasses a specified number of elements at the end of an observable sequence. This operator accumulates a queue with a length enough to store the first `count` elements. As more elements are received, elements are taken from the front of the queue and produced on the result sequence. This causes elements to be delayed. Args: count: Number of elements to bypass at the end of the source sequence. Returns: An observable sequence containing the source sequence elements except for the bypassed ones at the end. """ def subscribe( observer: abc.ObserverBase[_T], scheduler: Optional[abc.SchedulerBase] = None, ): q: List[_T] = [] def on_next(value: _T) -> None: front = None with source.lock: q.append(value) if len(q) > count: front = q.pop(0) if front is not None: observer.on_next(front) return source.subscribe( on_next, observer.on_error, observer.on_completed, scheduler=scheduler ) return Observable(subscribe) return skip_last __all__ = ["skip_last_"]