英文:
Which package contains merge function in golang
问题
我正在尝试在迭代中合并两个通道，以便可以在每个步骤中检索两个通道的值。
我写了以下代码：
ch1, ch2 := make(chan int), make(chan int)
go Walk(t1, ch1)
go Walk(t2, ch2)
for ints := range merge(ch1, ch2) {
fmt.Println(ints)
}
但是当我运行它时，我得到了"prog.go:31: undefined: merge"的错误。
我想知道这个merge函数在哪里。
英文:
I am trying to merge 2 channels in an iteration so that I can retrieve both channels values for each step.
I wrote the following lines
ch1, ch2 := make(chan int), make(chan int)
go Walk(t1, ch1)
go Walk(t2, ch2)
for ints := range merge(ch1, ch2) {
fmt.Println(ints)
}
but when I run it, I get "prog.go:31: undefined: merge".
I would like to know where this merge function is located.
答案1
得分: 13
标准库中没有这样的函数，你需要自己定义它。
从你的代码来看，似乎你已经阅读了这篇文章，其中已经给出了一个名为merge的用户定义函数的示例：
func merge(cs ...<-chan int) <-chan int {
var wg sync.WaitGroup
out := make(chan int)
// 为每个输入通道启动一个输出 goroutine。output 从 c 复制值到 out，直到 c 关闭，然后调用 wg.Done。
output := func(c <-chan int) {
for n := range c {
out <- n
}
wg.Done()
}
wg.Add(len(cs))
for _, c := range cs {
go output(c)
}
// 启动一个 goroutine，在所有输出 goroutine 完成后关闭 out。这必须在 wg.Add 调用之后启动。
go func() {
wg.Wait()
close(out)
}()
return out
}
来源：http://blog.golang.org/pipelines
英文:
There isn't such a function in the standard library, you'll have to define it yourself.
From your code, it seems that you've read this post which already gives an example of merge, a user-defined function:
func merge(cs ...<-chan int) <-chan int {
var wg sync.WaitGroup
out := make(chan int)
// Start an output goroutine for each input channel in cs. output
// copies values from c to out until c is closed, then calls wg.Done.
output := func(c <-chan int) {
for n := range c {
out <- n
}
wg.Done()
}
wg.Add(len(cs))
for _, c := range cs {
go output(c)
}
// Start a goroutine to close out once all the output goroutines are
// done. This must start after the wg.Add call.
go func() {
wg.Wait()
close(out)
}()
return out
}
source: http://blog.golang.org/pipelines
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