As a title, how to delete duplicate elements between slices on golang
ex.
a_array := {"1","2","3","4,"}
b_array := {"3","4"}
hope of result
"1","2"
With the assumption, a_array elements definitely has b_array elements. Please tell me how to do it. Thank you!
If you need to strictly compare one slice against the other you may do something along the lines of
func diff(a []string, b []string) []string {
// Turn b into a map
var m map[string]bool
m = make(map[string]bool, len(b))
for _, s := range b {
m[s] = false
}
// Append values from the longest slice that don't exist in the map
var diff []string
for _, s := range a {
if _, ok := m[s]; !ok {
diff = append(diff, s)
continue
}
m[s] = true
}
// Sort the resulting slice
sort.Strings(diff)
return diff
}
Alternatively if you want to get all values from both slices that are not present in both of them you can do
func diff(a []string, b []string) []string {
var shortest, longest *[]string
if len(a) < len(b) {
shortest = &a
longest = &b
} else {
shortest = &b
longest = &a
}
// Turn the shortest slice into a map
var m map[string]bool
m = make(map[string]bool, len(*shortest))
for _, s := range *shortest {
m[s] = false
}
// Append values from the longest slice that don't exist in the map
var diff []string
for _, s := range *longest {
if _, ok := m[s]; !ok {
diff = append(diff, s)
continue
}
m[s] = true
}
// Append values from map that were not in the longest slice
for s, ok := range m {
if ok {
continue
}
diff = append(diff, s)
}
// Sort the resulting slice
sort.Strings(diff)
return diff
}
Then
fmt.Println(diff(a_array, b_array))
will give you
[1 2]