# 4.4 Operator - 操作符 ![](https://4217506537-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MWj545abP2yK86-qksJ%2Fsync%2F7453e90f1222a35180ac687e227481daeb696dd7.png?generation=1616819388325680\&alt=media) **操作符**可以帮助大家创建新的序列，或者变化组合原有的序列，从而生成一个新的序列。 我们之前在[输入验证](https://3440217568.gitbook.io/rxswift/first_app)例子中就多次运用到操作符。例如，通过 [map](https://3440217568.gitbook.io/rxswift/decision_tree/map) 方法将**输入的用户名**，转换为**用户名是否有效**。然后用这个转化后来的序列来控制红色提示语是否隐藏。我们还通过 [combineLatest](https://3440217568.gitbook.io/rxswift/decision_tree/combinelatest) 方法，将**用户名是否有效**和**密码是否有效**合并成**两者是否同时有效**。然后用这个合成后来的序列来控制按钮是否可点击。 这里 [map](https://3440217568.gitbook.io/rxswift/decision_tree/map) 和 [combineLatest](https://3440217568.gitbook.io/rxswift/decision_tree/combinelatest) 都是**操作符**，它们可以帮助我们构建所需要的序列。现在，我们再来看几个例子： ## [filter](https://3440217568.gitbook.io/rxswift/decision_tree/filter) - 过滤 ![](https://4217506537-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MWj545abP2yK86-qksJ%2Fsync%2F184af266ebd9c672d0ff1fecb3a3b085877ae6a1.png?generation=1616819387747141\&alt=media) 你可以用 [filter](https://3440217568.gitbook.io/rxswift/decision_tree/filter) 创建一个新的序列。这个序列只发出温度大于 33 度的元素。 ## [map](https://3440217568.gitbook.io/rxswift/decision_tree/map) - 转换 ![](https://4217506537-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MWj545abP2yK86-qksJ%2Fsync%2F9699807f25bc79187d3e07f6ba8f4e702cda6a99.png?generation=1616819387966201\&alt=media) 你可以用 [map](https://3440217568.gitbook.io/rxswift/decision_tree/map) 创建一个新的序列。这个序列将原有的 **JSON** 转换成 **Model** 。这种转换实际上就是解析 **JSON** 。 ## [zip](https://3440217568.gitbook.io/rxswift/decision_tree/zip) - 配对 ![](https://4217506537-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MWj545abP2yK86-qksJ%2Fsync%2F4e1ca87c094988c35810ee7a3fc0107ff279b2d7.png?generation=1616819388409325\&alt=media) 你可以用 [zip](https://3440217568.gitbook.io/rxswift/decision_tree/zip) 来合成一个新的序列。这个序列将汉堡序列的元素和薯条序列的元素配对后，生成一个新的套餐序列。 ## 如何使用操作符 使用操作符是非常容易的。你可以直接调用实例方法，或者静态方法： * 温度过滤 ```swift // 温度 let rxTemperature: Observable = ... // filter 操作符 rxTemperature.filter { temperature in temperature > 33 } .subscribe(onNext: { temperature in print("高温：\(temperature)度") }) .disposed(by: disposeBag) ``` * 解析 JSON ```swift // JSON let json: Observable = ... // map 操作符 json.map(Model.init) .subscribe(onNext: { model in print("取得 Model: \(model)") }) .disposed(by: disposeBag) ``` * 合成套餐 ```swift // 汉堡 let rxHamburg: Observable = ... // 薯条 let rxFrenchFries: Observable = ... // zip 操作符 Observable.zip(rxHamburg, rxFrenchFries) .subscribe(onNext: { (hamburg, frenchFries) in print("取得汉堡: \(hamburg) 和薯条：\(frenchFries)") }) .disposed(by: disposeBag) ``` ## 决策树 [Rx](https://github.com/Reactive-Extensions/Rx.NET) 提供了充分的**操作符**来帮我们创建序列。当然如果内置操作符无法满足你的需求时，你还可以创建自定义的操作符。 如果你不确定该如何选择操作符，可以参考 [决策树](https://3440217568.gitbook.io/rxswift/decision_tree)。它会引导你找出合适的操作符。 ## 操作符列表 > 26个英文字母我都认识，可是连成一个句子我就不怎么认得了... 这里提供一个操作符列表，它们就好比是**26个英文字母**。你如果要将它们的作用全部都发挥出来，是需要学习如何将它们**连成一个句子**的： * [amb](https://3440217568.gitbook.io/rxswift/decision_tree/amb) * [buffer](https://3440217568.gitbook.io/rxswift/decision_tree/buffer) * [catchError](https://3440217568.gitbook.io/rxswift/decision_tree/catcherror) * [combineLatest](https://3440217568.gitbook.io/rxswift/decision_tree/combinelatest) * [concat](https://3440217568.gitbook.io/rxswift/decision_tree/concat) * [concatMap](https://3440217568.gitbook.io/rxswift/decision_tree/concatmap) * [connect](https://3440217568.gitbook.io/rxswift/decision_tree/connect) * [create](https://3440217568.gitbook.io/rxswift/decision_tree/create) * [debounce](https://3440217568.gitbook.io/rxswift/decision_tree/debounce) * [debug](https://3440217568.gitbook.io/rxswift/decision_tree/debug) * [deferred](https://3440217568.gitbook.io/rxswift/decision_tree/deferred) * [delay](https://3440217568.gitbook.io/rxswift/decision_tree/delay) * [delaySubscription](https://3440217568.gitbook.io/rxswift/decision_tree/delaysubscription) * [dematerialize](https://3440217568.gitbook.io/rxswift/decision_tree/dematerialize) * [distinctUntilChanged](https://3440217568.gitbook.io/rxswift/decision_tree/distinctuntilchanged) * [do](https://3440217568.gitbook.io/rxswift/decision_tree/do) * [elementAt](https://3440217568.gitbook.io/rxswift/decision_tree/elementat) * [empty](https://3440217568.gitbook.io/rxswift/decision_tree/empty) * [error](https://3440217568.gitbook.io/rxswift/decision_tree/error) * [filter](https://3440217568.gitbook.io/rxswift/decision_tree/filter) * [flatMap](https://3440217568.gitbook.io/rxswift/decision_tree/flatmap) * [flatMapLatest](https://3440217568.gitbook.io/rxswift/decision_tree/flatmaplatest) * [from](https://3440217568.gitbook.io/rxswift/decision_tree/from) * [groupBy](https://3440217568.gitbook.io/rxswift/decision_tree/groupby) * [ignoreElements](https://3440217568.gitbook.io/rxswift/decision_tree/ignoreelements) * [interval](https://3440217568.gitbook.io/rxswift/decision_tree/interval) * [just](https://3440217568.gitbook.io/rxswift/decision_tree/just) * [map](https://3440217568.gitbook.io/rxswift/decision_tree/map) * [merge](https://3440217568.gitbook.io/rxswift/decision_tree/merge) * [materialize](https://3440217568.gitbook.io/rxswift/decision_tree/materialize) * [never](https://3440217568.gitbook.io/rxswift/decision_tree/never) * [observeOn](https://3440217568.gitbook.io/rxswift/decision_tree/observeon) * [publish](https://3440217568.gitbook.io/rxswift/decision_tree/publish) * [reduce](https://3440217568.gitbook.io/rxswift/decision_tree/reduce) * [refCount](https://3440217568.gitbook.io/rxswift/decision_tree/refcount) * [repeatElement](https://3440217568.gitbook.io/rxswift/decision_tree/repeatelement) * [replay](https://3440217568.gitbook.io/rxswift/decision_tree/replay) * [retry](https://3440217568.gitbook.io/rxswift/decision_tree/retry) * [sample](https://3440217568.gitbook.io/rxswift/decision_tree/sample) * [scan](https://3440217568.gitbook.io/rxswift/decision_tree/scan) * [shareReplay](https://3440217568.gitbook.io/rxswift/decision_tree/sharereplay) * [single](https://3440217568.gitbook.io/rxswift/decision_tree/single) * [skip](https://3440217568.gitbook.io/rxswift/decision_tree/skip) * [skipUntil](https://3440217568.gitbook.io/rxswift/decision_tree/skipuntil) * [skipWhile](https://3440217568.gitbook.io/rxswift/decision_tree/skipwhile) * [startWith](https://3440217568.gitbook.io/rxswift/decision_tree/startwith) * [subscribeOn](https://3440217568.gitbook.io/rxswift/decision_tree/subscribeon) * [take](https://3440217568.gitbook.io/rxswift/decision_tree/take) * [takeLast](https://3440217568.gitbook.io/rxswift/decision_tree/takelast) * [takeUntil](https://3440217568.gitbook.io/rxswift/decision_tree/takeuntil) * [takeWhile](https://3440217568.gitbook.io/rxswift/decision_tree/takewhile) * [timeout](https://3440217568.gitbook.io/rxswift/decision_tree/timeout) * [timer](https://3440217568.gitbook.io/rxswift/decision_tree/timer) * [using](https://3440217568.gitbook.io/rxswift/decision_tree/using) * [window](https://3440217568.gitbook.io/rxswift/decision_tree/window) * [withLatestFrom](https://3440217568.gitbook.io/rxswift/decision_tree/withlatestfrom) * [zip](https://3440217568.gitbook.io/rxswift/decision_tree/zip)