Source code for paco.dropwhile

# -*- coding: utf-8 -*-
import asyncio
from .filter import filter
from .decorator import overload

[docs]@overload @asyncio.coroutine def dropwhile(coro, iterable, loop=None): """ Make an iterator that drops elements from the iterable as long as the predicate is true; afterwards, returns every element. Note, the iterator does not produce any output until the predicate first becomes false, so it may have a lengthy start-up time. This function is pretty much equivalent to Python standard `itertools.dropwhile()`, but designed to be used with async coroutines. This function is a coroutine. This function can be composed in a pipeline chain with ``|`` operator. Arguments: coro (coroutine function): coroutine function to call with values to reduce. iterable (iterable|asynchronousiterable): an iterable collection yielding coroutines functions. loop (asyncio.BaseEventLoop): optional event loop to use. Raises: TypeError: if coro argument is not a coroutine function. Returns: filtered values (list): ordered list of resultant values. Usage:: async def filter(num): return num < 4 await paco.dropwhile(filter, [1, 2, 3, 4, 5, 1]) # => [4, 5, 1] """ drop = False @asyncio.coroutine def assert_fn(element): nonlocal drop if element and not drop: return False if not element and not drop: drop = True return True if drop else element @asyncio.coroutine def filter_fn(element): return (yield from coro(element)) return (yield from filter(filter_fn, iterable, assert_fn=assert_fn, limit=1, loop=loop))