> 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/publish.md).

# publish

**将 `Observable` 转换为可被连接的 `Observable`**

![](/files/-MWlwKDC7DF5rekmrRXE)

**publish** 会将 `Observable` 转换为**可被连接的 `Observable`**。**可被连接的 `Observable`** 和普通的 `Observable` 十分相似，不过在被订阅后不会发出元素，直到 [connect](/rxswift/decision_tree/connect.md) 操作符被应用为止。这样一来你可以控制 `Observable` 在什么时候**开始**发出元素。

## 演示

```swift
let intSequence = Observable<Int>.interval(1, scheduler: MainScheduler.instance)
    .publish()

_ = intSequence
    .subscribe(onNext: { print("Subscription 1:, Event: \($0)") })

DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
    _ = intSequence.connect()
}

DispatchQueue.main.asyncAfter(deadline: .now() + 4) {
  _ = intSequence
      .subscribe(onNext: { print("Subscription 2:, Event: \($0)") })
}

DispatchQueue.main.asyncAfter(deadline: .now() + 6) {
  _ = intSequence
      .subscribe(onNext: { print("Subscription 3:, Event: \($0)") })
}
```

**输出结果：**

```swift
Subscription 1:, Event: 0
Subscription 1:, Event: 1
Subscription 2:, Event: 1
Subscription 1:, Event: 2
Subscription 2:, Event: 2
Subscription 1:, Event: 3
Subscription 2:, Event: 3
Subscription 3:, Event: 3
Subscription 1:, Event: 4
Subscription 2:, Event: 4
Subscription 3:, Event: 4
Subscription 1:, Event: 5
Subscription 2:, Event: 5
Subscription 3:, Event: 5
Subscription 1:, Event: 6
Subscription 2:, Event: 6
Subscription 3:, Event: 6
...
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://3440217568.gitbook.io/rxswift/decision_tree/publish.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.