Compare two slices

Question

Is there a way in Go to compare two slices and get the elements in slice X that are not in slice Y and vice versa?

    X := []int{10, 12, 12, 12, 13}
    Y := []int{12, 14, 15}

func compare(X, Y []int)  

calling compare(X, Y)   
    result1 := []int{10, 12, 12, 13} // if you're looking for elements in slice X that are not in slice Y

calling compare(Y, X)
    result2 := []int{14, 15} // if you're looking for elements in slice Y that are not in slice X

Answer 1

Something like this should work:

package main

import "fmt"

func main() {
    X := []int{10, 12, 12, 12, 13}
    Y := []int{12, 14, 15}

    fmt.Println(compare(X, Y))
    fmt.Println(compare(Y, X))
}

func compare(X, Y []int) []int {
    m := make(map[int]int)

    for _, y := range Y {
        m[y]++
    }

    var ret []int
    for _, x := range X {
        if m[x] > 0 {
            m[x]--
            continue
        }
        ret = append(ret, x)
    }

    return ret
}

http://play.golang.org/p/4DujR2staI