这是接口列表的参数{} [重复]

Question

This question already has an answer here:

• Passing interface{} or []interface{} in Golang 1 answer

I'm trying to create a function that prints out the len of a list passed into it, regardless of the type of the list. My naive way of doing this was:

func printLength(lis []interface{}) {
    fmt.Printf("Length: %d", len(lis))
}

However, when trying to use it via

func main() {
    strs := []string{"Hello,", "World!"}
    printLength(strs)
}

It complains saying

cannot use strs (type []string) as type []interface {} in argument to printLength

But, a string can be used as a interface{}, so why can't a []string be used as a []interface{}?

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Answer 1

You can use reflect package - playground

import (
    "fmt"
    "reflect"
)
func printLength(lis interface{}) {
    fmt.Printf("Length: %d", reflect.ValueOf(lis).Len())
}