Hands-On Reactive Programming with Python

The from_future operator

The from_future operator converts a future object to an observable that emits zero, or one item. The marble diagram of this operator is shown in the following figure:

Figure 4.18: The from_future operator

Its prototype is as follows:

Observable.from_future(future)

This operator converts future to an observable that emits the result of future if it succeeds, or the error raised by future if it does not. The following is an example of its usage:

import asynciofrom rx import Observableasync def foo(future):    await asyncio.sleep(1)    future.set_result(2)loop = asyncio.get_event_loop()done = loop.create_future()asyncio.ensure_future(foo(done)) ...