Wsrtjtyk

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

}

Go Playground

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]

Go playground