Tickers {.en}

行情 {.zh}

::: {.en} Timers are for when you want to do something once in the future - tickers are for when you want to do something repeatedly at regular intervals. Here’s an example of a ticker that ticks periodically until we stop it. :::

::: {.zh}

定时器 是当你想要在未来某一刻执行一次时 使用的 - 打点器 则是当你想要在固定的时间间隔重复执行 准备的。这里是一个打点器的例子，它将定时的执行，直到我 们将它停止。

:::

package main
import "time"
import "fmt"
func main() {

::: {.en} Tickers use a similar mechanism to timers: a channel that is sent values. Here we’ll use the range builtin on the channel to iterate over the values as they arrive every 500ms. :::

::: {.zh}

打点器和定时器的机制有点相似：一个通道用来发送数据。 这里我们在这个通道上使用内置的 range 来迭代值每隔 500ms 发送一次的值。

:::

    ticker := time.NewTicker(500 * time.Millisecond)
    go func() {
        for t := range ticker.C {
            fmt.Println("Tick at", t)
        }
    }()

::: {.en} Tickers can be stopped like timers. Once a ticker is stopped it won’t receive any more values on its channel. We’ll stop ours after 1600ms. :::

::: {.zh}

打点器可以和定时器一样被停止。一旦一个打点停止了， 将不能再从它的通道中接收到值。我们将在运行后 1600ms 停止这个打点器。

:::

    time.Sleep(1600 * time.Millisecond)
    ticker.Stop()
    fmt.Println("Ticker stopped")
}

::: {.en} When we run this program the ticker should tick 3 times before we stop it. :::

::: {.zh}

当我们运行这个程序时，这个打点器会在我们停止它前打点 3 次。

:::

$ go run tickers.go
Tick at 2012-09-23 11:29:56.487625 -0700 PDT
Tick at 2012-09-23 11:29:56.988063 -0700 PDT
Tick at 2012-09-23 11:29:57.488076 -0700 PDT
Ticker stopped