Do Sets exist in Go? (like in Python)

Question

Is there any Go collection similar to 'Set's in python?

alternatives:

• Is there an easy way of implementing Sets in Go?
• Is there any method to eliminate duplicates in a slice?

Answer 1

You could just have a map[whatevertype]bool and set the value to true. You could add every element in a slice as a map key, then use a range to get only the unique ones back out.

package main
import "fmt"
func main() {
    m := make(map[string]bool)
    s := make([]string, 0)
    s = append(s, "foo")
    s = append(s, "foo")
    s = append(s, "foo")
    s = append(s, "bar")
    s = append(s, "bar")
    for _, r := range s {
        m[r] = true
    }
    s = make([]string, 0)
    for k, _ := range m {
        s = append(s, k)
    }
    fmt.Printf("%v\n", s)
}

Answer 2

I think the map[T]bool is the best option, but another option is map[T]struct{}:

package main

func main() {
   { // example 1
      s := make(map[string]struct{})
      s["north"] = struct{}{}
      s["south"] = struct{}{}
      _, ok := s["north"]
      println(ok)
   }
   { // example 2
      s := map[string]struct{}{
         "north": {}, "south": {},
      }
      _, ok := s["north"]
      println(ok)
   }
}

it's not as easy to work with, but it takes up less memory if that is a factor for you.