Maps¶

package main

import (
    "fmt"
    "sort"
)

var (
    barVal = map[string]int{
        "alpha":   1,
        "bravo":   2,
        "charlie": 3,
        "delta":   4,
        "echo":    5,
        "foxtrot": 6,
    }
)

func main() {
    fmt.Println("**unsorted:**  ")
    for k, v := range barVal {
        fmt.Printf("%v -> %v  \n", k, v) // read random keys
    }
    keys := make([]string, len(barVal)) // storing all keys in separate slice
    i := 0
    for k := range barVal {
        keys[i] = k
        i++
    }
    sort.Strings(keys) // sorting the keys slice

    fmt.Println("\n**sorted:**  ")
    for _, k := range keys {
        fmt.Printf("%v -> %v  \n", k, barVal[k]) // reading key from keys and value from barVal
    }
}

package main

import (
    "fmt"
)

var (
    barVal = map[string]int{
        "alpha":   34,
        "bravo":   56,
        "charlie": 23,
        "delta":   87,
        "echo":    56,
        "foxtrot": 12,
        "golf":    34,
        "hotel":   16,
        "indio":   87,
        "juliet":  65,
        "kilo":    43,
        "lima":    98,
    }
)

func main() {
    invMap := make(map[int][]string, len(barVal)) // interchanging types of keys and values
    for k, v := range barVal {
        if _, ok := invMap[v]; ok {
            invMap[v] = append(invMap[v], ",") // add comma before adding another value
        }
        invMap[v] = append(invMap[v], k) // key becomes value and value becomes key
    }
    fmt.Println("**inverted:**  ")
    for k, v := range invMap {
        fmt.Printf("%v -> %v  \n", k, v)
    }
}