Learning RxJava - Second Edition

toList()

The toList() is probably the most often used among all the collection operators. For a given Observable<T>, it collects incoming items into a List<T> and then pushes that List<T> object as a single value through Single<List<T>.

In the following code snippet, we collect String values into a List<String>. After the preceding Observable signals onComplete(), that list is pushed into the Observer to be printed:

import io.reactivex.rxjava3.core.Observable;public class Ch3_30 {    public static void main(String[] args) {        Observable.just("Alpha", "Beta", "Gamma")                .toList()                .subscribe(s -> System.out.println("Received: " + s));    }}

The output of the preceding code snippet is as follows:

Received: [Alpha, Beta, Gamma]

By default, toList()