函数返回后，在数组的struct成员上设置的值丢失

Question

In golang, my understanding was that array slice types are references. I've got a problem where golang is acting like it is making copies of the data, rather than passing references around.

https://play.golang.org/p/EfEOMV_wcS

type Temp struct {
    Id   string `json:"id"`
    Lost string `json:"lost"`
}

func makeFoo1() []Temp {
    foos := make([]Temp, 0)
    foos = append(foos, Temp{Id: "foo"})
    return foos
}

func makeFoo2() []Temp {
    foos := makeFoo1()
    for _, t := range foos {
        t.Lost = "lost"
    }
    return foos

}

func main() {
    j, _ := json.Marshal(makeFoo2())
    fmt.Printf("%s
", j)
}

The output of this is [{"id":"foo","lost":""}]

How can the assignment t.Lost = "..." be made in makeFoo2 so it doesn't get lost? Or I guess the real question is how do I ensure the array is a reference and not a value?

Answer 1

I figured this out myself - what range returns is actually a copy. This fixed it

func makeFoo2() []Temp {
    foos := makeFoo1()
    for i, _ := range foos {
        foos[i].Lost = "lost"

    }
    return foos

}