如何从[] interface {}转换为[] int？ [重复]

Question

This question already has an answer here:

• Type converting slices of interfaces 5 answers

I would like to get non duplicated []int. I'm using set, but I don't know how to get []int from set. How can I do that?

package main

import (
    "fmt"
    "math/rand"
    "time"

    "github.com/deckarep/golang-set"
)

func pickup(max int, num int) []int {
    set := mapset.NewSet()

    rand.Seed(time.Now().UnixNano())
    for set.Cardinality() < num {
        n := rand.Intn(max)
        set.Add(n)
    }
    selected := set.ToSlice()
    // Do I need to cast from []interface{} to []int around here?
    // selected.([]int) is error.
    return selected
}

func main() {
    results := pickup(100, 10)
    fmt.Println(results)
    // some processing using []int...
}

</div>

Answer 1

There is no automatic way to do that. You need to create an int slice and copy into it:

selected := set.ToSlice()

// create a secondary slice of ints, same length as selected
ret := make([]int, len(selected))

// copy one by one
for i, x := range selected {
   ret[i] = x.(int) //provided it's indeed int. you can add a check here
}

return ret