Hands-On Reactive Programming with Python

The take_while operator

The take_while operator emits items from the source observable until a criterion is met. The following figure shows the marble diagram of this operator:

Figure 9.34: The take_while operator

Its prototype is the following:

Observable.take_while(self, predicate)

Here, predicate is a function called each time an item is emitted form the source observable. When the predicate function returns True, then the take_while operator stops emitting items of the source observable.

Here is an example of the take_while operator:

numbers = Observable.from_([1, 2, 3, 4])numbers.take_while(lambda i: i < 2).subscribe( on_next = lambda ...