How to Create a Map of Maps in Go

We can create a map of maps in Go by using the map data structure. This example demonstrates creating a map where both the outer and inner maps use integers for keys and values.

For example,

package main

import "fmt"

func main() {
    // Declare a map of maps
    outerMap := make(map[int]map[int]int)

    // Populate the inner maps
    innerMap1 := map[int]int{1: 10, 2: 20, 3: 30}
    innerMap2 := map[int]int{4: 40, 5: 50, 6: 60}

    // Insert the inner maps into the outer map
    outerMap[1] = innerMap1
    outerMap[2] = innerMap2

    // Print the resulting map of maps
    fmt.Println("Map of maps with integer keys and values:")
    for outerKey, innerMap := range outerMap {
        fmt.Printf("Outer key: %d\n", outerKey)
        for innerKey, value := range innerMap {
            fmt.Printf("  Inner key: %d, value: %d\n", innerKey, value)
        }
    }
}

Map of maps with integer keys and values:
Outer key: 1
  Inner key: 1, value: 10
  Inner key: 2, value: 20
  Inner key: 3, value: 30
Outer key: 2
  Inner key: 4, value: 40
  Inner key: 5, value: 50
  Inner key: 6, value: 60

We can create a map of maps in Go by using the map data structure. This example demonstrates creating a map where the outer map uses strings for keys and the inner maps use integers for keys and strings for values.

For example,

package main

import "fmt"

func main() {
    // Declare a map of maps
    outerMap := make(map[string]map[int]string)

    // Populate the inner maps
    innerMap1 := map[int]string{1: "one", 2: "two", 3: "three"}
    innerMap2 := map[int]string{4: "four", 5: "five", 6: "six"}

    // Insert the inner maps into the outer map
    outerMap["first"] = innerMap1
    outerMap["second"] = innerMap2

    // Print the resulting map of maps
    fmt.Println("Map of maps with mixed key and value types:")
    for outerKey, innerMap := range outerMap {
        fmt.Printf("Outer key: %s\n", outerKey)
        for innerKey, value := range innerMap {
            fmt.Printf("  Inner key: %d, value: %s\n", innerKey, value)
        }
    }
}

Map of maps with mixed key and value types:
Outer key: first
  Inner key: 1, value: one
  Inner key: 2, value: two
  Inner key: 3, value: three
Outer key: second
  Inner key: 4, value: four
  Inner key: 5, value: five
  Inner key: 6, value: six

We can create a map of maps in Go by using the map data structure. This example demonstrates creating a map where both the outer and inner maps use strings for keys and float64 for values.

For example,

package main

import "fmt"

func main() {
    // Declare a map of maps
    outerMap := make(map[string]map[string]float64)

    // Populate the inner maps
    innerMap1 := map[string]float64{"A": 1.1, "B": 2.2, "C": 3.3}
    innerMap2 := map[string]float64{"D": 4.4, "E": 5.5, "F": 6.6}

    // Insert the inner maps into the outer map
    outerMap["group1"] = innerMap1
    outerMap["group2"] = innerMap2

    // Print the resulting map of maps
    fmt.Println("Map of maps with string keys and float64 values:")
    for outerKey, innerMap := range outerMap {
        fmt.Printf("Outer key: %s\n", outerKey)
        for innerKey, value := range innerMap {
            fmt.Printf("  Inner key: %s, value: %.1f\n", innerKey, value)
        }
    }
}

Map of maps with string keys and float64 values:
Outer key: group1
  Inner key: A, value: 1.1
  Inner key: B, value: 2.2
  Inner key: C, value: 3.3
Outer key: group2
  Inner key: D, value: 4.4
  Inner key: E, value: 5.5
  Inner key: F, value: 6.6