how to compare two arrays is same with any orders value in golang

Question

I'm still new in golang. I want to know how I check if two arrays are considered equal if those arrays contain the same values in any order. I have read answers in this Comparing arrays in Go language and I know if I use == the arrays are considered equal if those arrays contain the same value in the same order.

for example, I want these arrays considered equal.

a := [3]int{1,2,3}
b := [3]int{3,2,1}

Answer 1

With Go 1.18 or later, you can use sort.Ints to sort the arrays before comparison, and then slices.Equal to compared the sorted slices. Something like:

func EqualIgnoringOrder(a, b []int) bool {
    if len(a) != len(b) {
        return false
    }

    sort.Ints(a)
    sort.Ints(b)

    return slices.Equal(a, b)
}

You would use it like this:

package main

import (
    "fmt"
    "sort"

    "golang.org/x/exp/slices"
)

func EqualIgnoringOrder(a, b []int) bool {
    if len(a) != len(b) {
        return false
    }

    sort.Ints(a)
    sort.Ints(b)

    return slices.Equal(a, b)
}

func main() {
    a := []int{1, 2, 3}
    b := []int{3, 2, 1}

    if EqualIgnoringOrder(a, b) {
        fmt.Println("arrays are equal")
    } else {
        fmt.Println("arrays are not equal")
    }
}

Notice that here I'm using slices rather than arrays; to quote https://go.dev/blog/slices , "Arrays are not often seen in Go programs because the size of an array is part of its type, which limits its expressive power."

We can't use == to compare slices, which is why we use slices.Equal (which is only available for go 1.18 or later).