Populate map values from channel response in golang - dictionary

Question

I am trying to populate a map based on output from various goroutines. For this I have created a channel of type (map[key][]int)
done := make(chan map[int][]int)
and pass it to workers goroutine, along with the key value, which is int for the example.
for i := 0; i < 10; i++ {
go worker(i, done)
}
I want to populate my map as I read from the key. Currently I am doing as below
for i := 0; i < 10; i++ {
m := <-done
fmt.Println(m)
for k,v := range m {
retmap[k] = v
}
}
fmt.Println(retmap)
I feel I am not doing this correctly. Is there a better way to do this using channels? Any suggestions would be much appreciated?
playground: https://play.golang.org/p/sv4Qk4hEljx

Answer 1

You could use a specific channel per worker instead of encoding that information in the result object of the worker. Something like:
func worker(done chan []int) {
fmt.Print("working...")
rnd := rand.Intn(10)
fmt.Println("Sleeping for ", rnd, "seconds")
for i := 0; i < rnd; i++ {
time.Sleep(time.Second)
}
fmt.Println("done")
// Send a value to notify that we're done.
done <- makeRange(0, rnd)
}
func main() {
channels := make([]chan []int, 10, 10)
for i := 0; i < 10; i++ {
channels[i] = make(chan []int)
go worker(channels[i])
}
retmap := make(map[int][]int)
for i := 0; i < 10; i++ {
retmap[i] = <-channels[i]
}
fmt.Println(retmap)
}
Playground link