Set implementation in Golang

A set is a data structure that holds elements without any particular order. An element only appears once in a set.

Set can be implemented in GO using a map. We will be using map[string]struct{} for the set as struct{} occupies no memory hence more efficient in terms of storage.
Below is the simple example of set having operations

1. Add
2. Remove
3. Exists

package main
import (
"fmt"
)
//MakeSet initialize the set
func makeSet() *customSet {
return &customSet{
container: make(map[string]struct{}),
}
}
type customSet struct {
container map[string]struct{}
}
func (c *customSet) Exists(key string) bool {
_, exists := c.container[key]
return exists
}
func (c *customSet) Add(key string) {
c.container[key] = struct{}{}
}
func (c *customSet) Remove(key string) error {
_, exists := c.container[key]
if !exists {
return fmt.Errorf("Remove Error: Item doesn't exist in set")
}
delete(c.container, key)
return nil
}
func (c *customSet) Size() int {
return len(c.container)
}
func main() {
customSet := makeSet()
fmt.Printf("Add: B\n")
customSet.Add("A")
fmt.Printf("Add: B\n")
customSet.Add("B")
fmt.Printf("Size: %d\n", customSet.Size())
fmt.Printf("A Exists?: %t\n", customSet.Exists("A"))
fmt.Printf("B Exists?: %t\n", customSet.Exists("B"))
fmt.Printf("C Exists?: %t\n", customSet.Exists("C"))
fmt.Printf("Remove: B\n")
customSet.Remove("B")
fmt.Printf("B Exists?: %t\n", customSet.Exists("B"))
}

Output:

Add: B
Add: B
Size: 2
A Exists?: true
B Exists?: true
C Exists?: false
Remove: B
B Exists?: false