Map as a set

package main

import "fmt"

func main() {

	var stringSet map[string]interface{} = make(map[string]interface{})

	stringSet["apple"] = nil
	stringSet["orange"] = nil
	stringSet["cherry"] = nil
	// O(1) vs O(n). Only matters for large lists
	if _, ok := stringSet["apple"]; !ok {
		fmt.Println("apple not in stringset")
	}
	if _, ok := stringSet["banana"]; !ok {
		fmt.Println("banana not in stringset")
	}
}