https://tour.go-zh.org/moretypes/20
package main import ( "golang.org/x/tour/wc" "strings" ) func WordCount(s string)(m map[string]int) { m = make(map[string]int) ss := strings.Fields(s) for _, v := range ss { m[v] = m[v] + 1 } return } func main() { wc.Test(WordCount) }