> For the complete documentation index, see [llms.txt](https://3440217568.gitbook.io/rxswift/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://3440217568.gitbook.io/rxswift/decision_tree/filter.md).

# filter

**仅仅发出 `Observable` 中通过判定的元素**

![](/files/-MWlwRRJcAokcrznnvvi)

**filter** 操作符将通过你提供的判定方法过滤一个 `Observable`。

## 演示

```swift
let disposeBag = DisposeBag()

Observable.of(2, 30, 22, 5, 60, 1)
          .filter { $0 > 10 }
          .subscribe(onNext: { print($0) })
          .disposed(by: disposeBag)
```

**输出结果：**

```swift
30
22
60
```