Slide 44
Slide 44 text
FoldLeft
1 def myFoldLeft[B](z: B)(f: (B, A) => B): Observable[B] =
2 Observable.create(observer => {
3 var acc = z
4 o.subscribe(
5 (a: A) => acc = f(acc, a),
6 observer.onError _,
7 () => {
8 observer.onNext(acc)
9 observer.onCompleted()
10 })
11 })
methods like single() force a result
but are blocking
Careful
foldLeft(0)(_ + _)