Maps / Maps with slices as values / Essential Go

package main

import (
	"fmt"
)

func main() {
	m := make(map[string][]int)
	fmt.Printf("Non-existing key returns zero value of []int, i.e. nil: %#v\n", m["key1"])

	m["key1"] = append(m["key1"], 8)
	m["key1"] = append(m["key1"], 3)
	fmt.Printf("\nAfter appending to slice: %#v\n", m["key1"])

	delete(m, "key1")
	fmt.Printf("\ndelete() sets back to nil slice: %#v\n", m["key1"])

}