golang [] interface {}是否不能用作函数参数？ [重复]

Question

This question already has an answer here:

• Type converting slices of interfaces 5 answers

My code :

---

package sort_test

type SortList []interface{}

type SortFunc func(interface{}, interface{}) bool


func Do(list SortList, function SortFunc)

---

main package

---

package main

import (
        "sort_test"
)

func main() {

    list := []int{3, 4, 5, 6, 6, 77, 4, 4, 5, 6, 8, 345, 45, 424, 2, 67, 7, 830}

slice := list[:]

sort_test.Do(slice, function)
}

---

compile error

src/algorithm/algorithm.go:32: cannot use slice (type []int) as type sort_test.SortList in argument to sort_test.Do
src/algorithm/algorithm.go:32: cannot use function (type func(int, int) bool) as type sort_test.SortFunc in argument to sort_test.Do
make: *** [algorithm] Error 2

</div>

Answer 1

Cannot. Interface is interface.

interface{} is not some kind of "any" type. But, any type implements interface{}. Interface is just a set of methods which should be implemented.

If you want to check whether the interface{} is slice or not, you can write it like this:

import "reflect"

t := reflect.TypeOf(list)
if t.Kind() == reflect.Slice {
    ...
}

I recommend you read this very helpful article: http://blog.golang.org/laws-of-reflection.

Additionally, it will be nice to read the code of sort package: https://golang.org/pkg/sort/. It is an example of golang-way implementation of sorting.

Edit: If you really really want use []interface{} as a parameter, actually you can do it like this:

vs := make([]interface{}, len(list))
for i, e := range list {
    vs[i] = e
}
Do(vs, f)

In fact, []interface{} is not an empty interface. It's a slice type whose elements are interface{}; []int is not []interface{}, but just implements interface{}.

I guess you want to write some kind of a general sorting method, like you write it by using generics in Java. I think it is a bad code.