Hands-On Reactive Programming with Python

The map operator

Let's see a real example with the map operator. This operator takes a source observable as input and returns an observable as output. It applies a function to each item of the source observable, and emits the result of this function on the output observable. Hopefully, its marble diagram, shown in the following figure, should make the description much more clear:

Figure 1.10: The map operator

The marble diagram shows an input timeline with three integer items: 1, 12, and 7. The transformation is described with syntax similar to that of the Python lambda. Note that the official ReactiveX documentation uses the JavaScript arrow ...