Implementing a set using a map
A set is useful to remove duplicates from a collection of values. Maps can be used as sets efficiently by utilizing a zero-size value structure.
How to do it...
Use a map whose key type is the element type of the set, and whose value type is struct{}:
stringSet := make(map[string]struct{}) Add values to the set with the struct{}{} value:
stringSet[value]=struct{}{} Check for value existence using the two-value version of map lookup:
if _,exists:=stringSet[str]; exists {
  // String str exists in the set
} A map is not ordered. If the ordering of elements is important, keep a slice with the map:
// Remove duplicate inputs from the input, preserving order
func DedupOrdered(input []string) []string {
   set:=make(map[string]struct{})
   output:=make([]string,0,len(input))
   for _,in:=range input {
     if _,exists:=set[in]; exists {
   ...
