A set is used to only store keys. Go doesn't have a set type, so a map of the type to a Boolean value is used frequently in order to build a set. The following code block is an implementation of an STL equivalent set:

package main

import "fmt"

func main() {
    s := make(map[int]bool)

    for i := 0; i < 5; i++ {
        s[i] = true
    }

    delete(s, 4)

    if s[2] {
        fmt.Println("s[2] is set")
    }
    if !s[4] {
        fmt.Println("s[4] was deleted")
    }
}

The resulting output shows that we were able to set and delete the values accordingly:

We can see from our output that our code can properly manipulate a set, which is crucial for common key–value pairings.