https://tour.golang.org/moretypes/23

exercise-maps.go

package main

import (
	"golang.org/x/tour/wc"
	"strings"
)

func WordCount(s string) map[string]int {
	sArr := strings.Fields(s)
	count := make(map[string]int)

	for index := range sArr {
		ele, ok := count[sArr[index]]
		if ok {
			count[sArr[index]] = ele + 1
		} else {
			count[sArr[index]] = 1
		}
	}
	return count
}

func main() {
	wc.Test(WordCount)
}