RXSwift - transform operators (t

toArray : 是把 observable 结束时所有的事件值变成一个数组，只要这个 observable 不结束，这个转变就不会发生。

        let bag = DisposeBag()
        
        let number = PublishSubject<Int>()
        
        number.asObserver().toArray().subscribe { (arr) in
            print("toArray  \(arr)")
        }.disposed(by: bag)
        
        number.onNext(1)
        number.onNext(2)
        number.onNext(3)
        number.onCompleted()

scan ：它可以对observable序列中的每一个事件进行 “累加”, 最终订阅到的 “累加” 的结果。

        let bag = DisposeBag()
        
        let number = PublishSubject<Int>()
        
        number.scan(0) { (old, new) -> Int in
            return old + new
        }.subscribe { (num) in
            print("scan  \(num)")
        }.disposed(by: bag)
        
        number.onNext(1)
        number.onNext(2)
        number.onNext(3)
        number.onCompleted()

note

map ：自定义事件变化行为

        let bag = DisposeBag()
        
        let number = PublishSubject<Int>()
        
        number.map { (value) -> Int in
            return value * value
        }.subscribe { (num) in
            print("map  \(num)")
        }.disposed(by: bag)
        
        number.onNext(1)
        number.onNext(2)
        number.onNext(3)
        number.onCompleted()

note