doubi1624 2018-02-18 22:38
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通道就绪后,从多个通道中选择所有值

I'm new in golang and I faced with the problem.

I have several channels.

Some payload gets to this channels in different time.

How I can get all values one by one from channels in the time when channel ready to spit it.

For example I wrote this code:

package main

import (
    "fmt"
    "time"
    "math/rand"
)

func main() {
    arr1 := []int8{1,2,3,4,5}
    arr2 := []int8{6,7,8,9,10}

    c1 := make(chan int8)
    c2 := make(chan int8)

    go func() {
        for _, val := range arr1 {
            time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
            c1 <- val
        }
    }()
    go func() {
        for _, val := range arr2 {
            time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
            c2 <- val
        }
    }()

    select {
        case res1 := <- c1:
            fmt.Println(res1)
        case res2 := <- c2:
            fmt.Println(res2)
    }

    fmt.Println("Hello, test")
}

But in this case, I get only first value, from one of the channels.

Please, give me advise how to solve my issue.

Link to go-play https://play.golang.org/p/FOmkP57YCyR

  • 写回答

3条回答 默认 最新

  • duanpo1498 2018-02-19 00:17
    关注

    You have to do couple of things.

    1) Make sure you close channels once you are done with source. 2) Iterate over channels until it's closed.

    Example:

    package main
    
    import (
        "fmt"
        "math/rand"
        "time"
    )
    
    func main() {
        arr1 := []int8{1, 2, 3, 4, 5}
        arr2 := []int8{6, 7, 8, 9, 10}
    
        c1 := make(chan int8)
        c2 := make(chan int8)
    
        go func() {
            for _, val := range arr1 {
                time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
                c1 <- val
            }
            close(c1)
        }()
        go func() {
            for _, val := range arr2 {
                time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
                c2 <- val
            }
            close(c2)
        }()
    
        _c1 := true
        _c2 := true
        var res1, res2 int8
    
        for _c1 == true || _c2 == true {
            select {
            case res1, _c1 = <-c1:
                if _c1 == true {
                    fmt.Println(res1)
                }
            case res2, _c2 = <-c2:
                if _c2 == true {
                    fmt.Println(res2)
                }
            }
        }
    
        fmt.Println("Hello, test")
    }
    

    On execution, I got following output on screen.

    6
    1
    7
    2
    3
    4
    8
    5
    9
    10
    Hello, test
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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