# Select

{% hint style="warning" %}
This page is under active revision, content may be updated without notice
{% endhint %}

In Go,  `select` statement lets a goroutine wait on multiple communication operations. A `select` blocks until one of its cases can run, then it executes that case. It chooses one at random if multiple are ready. Combining goroutines and channels with select is a powerful feature of Go.

```go
c1 := make(chan string)
c2 := make(chan string)
go func() {
    time.Sleep(time.Second * 1)
    c1 <- "Hello"
}()
go func() {
    time.Sleep(time.Second * 2)
    c2 <- "World"
}()
for {
    select {
        case msg1 := <-c1:
            fmt.Println("Received first message: ", msg1)
        case msg2 := <-c2:
            fmt.Println("Received second message: ", msg2)
            return
    }
}
```

Here we have put `select` statement within indefinite `for` loop. So It will keep on listening to channels unless it returns by calling `return` in one of them. In illustration above, when first anonymous goroutine function is called, it returns "Hello" to channel that in turn printed on I/O module (in our case cli), but select it does not finish, its ready to listens to another round of call and then second anonymous function is called and that does return, returning from select. And hence program exits

Golang's select lets you wait on multiple channel operations. Combining goroutines and channels with select is a powerful feature of Go.&#x20;

Go, also provides `default` case when no other cases match, default will run. In simplest form it would look like following

```go
select {
case i := <-c:
    // use i
default:
    // receiving from c would block
}
```


---

# Agent Instructions: 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://golang.bagwanpankaj.com/advanced-go/channel-select.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.