需要将2维数组转换为字符串，并用句号替换最后一个逗号。（Golang）

How can I create string out of multi-dimensional array, preferably using goroutine or channel, in order to replace the last comma of the element with a full-stop?

Thanks

package main

import (
    "fmt"
)

func main() {
    pls := [][]string {
       {"C", "C++"},
       {"JavaScript"},
       {"Go", "Rust"},
    }
    for _, v1 := range pls {
        for _, v2 := range v1 {
            fmt.Print(v2,", ")
        }
    }
}

I guess classic strings.Join would be easier to implement and maintain:

package main

import (
    "fmt"
    "strings"
)

func main() {
    pls := [][]string{
        {"C", "C++"},
        {"JavaScript"},
        {"Go", "Rust"},
    }

    var strs []string

    for _, v1 := range pls {
        s := strings.Join(v1, ", ")
        strs = append(strs, s)

    }
    s := strings.Join(strs, ", ")
    fmt.Println(s)
}

https://play.golang.org/p/2Nuv00PV5j