Source code for paco.flat_map

# -*- coding: utf-8 -*-
import asyncio
from .assertions import isiter
from .reduce import reduce
from .decorator import overload
from .assertions import assert_corofunction, assert_iter

[docs]@overload @asyncio.coroutine def flat_map(coro, iterable, limit=0, loop=None, timeout=None, return_exceptions=False, initializer=None, *args, **kw): """ Concurrently iterates values yielded from an iterable, passing them to an asynchronous coroutine. This function is the flatten version of to ````. Mapped values will be returned as an ordered list. Items order is preserved based on origin iterable order. Concurrency level can be configurable via ``limit`` param. All coroutines will be executed in the same loop. This function is a coroutine. This function can be composed in a pipeline chain with ``|`` operator. Arguments: coro (coroutinefunction): coroutine iterator function that accepts iterable values. iterable (iterable|asynchronousiterable): an iterable collection yielding coroutines functions. limit (int): max iteration concurrency limit. Use ``0`` for no limit. collect (bool): return yielded values from coroutines. Default False. loop (asyncio.BaseEventLoop): optional event loop to use. return_exceptions (bool): enable/disable returning exceptions in case of error. `collect` param must be True. timeout (int|float): timeout can be used to control the maximum number of seconds to wait before returning. timeout can be an int or float. If timeout is not specified or None, there is no limit to the wait time. *args (mixed): optional variadic arguments to pass to the coroutine iterable function. Returns: results (list): ordered list of values yielded by coroutines Raises: TypeError: in case of invalid input arguments. Usage:: async def mul_2(num): return num * 2 await paco.flat_map(mul_2, [1, [2], [3, [4]], [(5,)]]) # => [2, 4, 6, 8, 10] # Pipeline style await [1, [2], [3, [4]], [(5,)]] | paco.flat_map(mul_2) # => [2, 4, 6, 8, 10] """ assert_corofunction(coro=coro) assert_iter(iterable=iterable) # By default do not collect yielded values from coroutines results = initializer if isiter(initializer) else [] @asyncio.coroutine def reducer(buf, value): if isiter(value): yield from _reduce(value) else: buf.append((yield from coro(value))) return buf def _reduce(iterable): return reduce(reducer, iterable, initializer=results, limit=limit, loop=loop) # Returns list of mapped reduced results return (yield from _reduce(iterable))