如何在golang中修改作为结构的slice元素？

You have a golang slice of structs and you would like to change one entry in there.

type Type struct {
    value int
}

func main() {

    s := []Type{{0}, {0}}

    // Prints  [{0} {0}]
    fmt.Println(s)

    firstEntry := s[0]
    firstEntry.value = 5

    // Also prints [{0} {0}]
    fmt.Println(s)
}

https://play.golang.org/p/32tpcc3-OD

Using the brackets operator and modifying its return does not change the slice itself.

What is the recommended way of doing this slice entry modification ?

Try

s[0].value = 5

This gets to the backing store of the slice. Also

p := &s[1]
p.value = 6

It looks like the brackets operator on a slice in golang returns by value.

I was assuming C++ stl vector like semantics where references are returned. (http://en.cppreference.com/w/cpp/container/vector/operator_at)

One needs to assign the modified values back to the slice indexes.

type Type struct {
    value int
}

func main() {

    s := []Type{{0}, {0}}

    // Prints  [{0} {0}]
    fmt.Println(s)

    firstEntry := s[0]
    firstEntry.value = 5

    // Prints  [{0} {0}]
    fmt.Println(s)

    s[0] = firstEntry

    // Prints [{5} {0}]
    fmt.Println(s)
}

https://play.golang.org/p/dMKqNgMda3

You can also take the address of the slice element directly and de-reference it:

func main() {

    s := []Type{{0}, {0}}

    // Prints  [{0} {0}]
    fmt.Println(s)

    // De-reference the address of the slice element
    (&s[0]).value = 5

    // Prints [{5} {0}]
    fmt.Println(s)
}