pointersreferencego

Range references instead values


I saw that range returns the key and the "copy" of the value. Is there a way for that range to return the address of the item? Example

package main

import "fmt"

type MyType struct {
    field string
}

func main() {
    var array [10]MyType

    for _, e := range array {
        e.field = "foo"
    }

    for _, e := range array {
        fmt.Println(e.field)
        fmt.Println("--")
    }
}

http://play.golang.org/p/AFOGG9NGpx

Here "field" is not modified because range sends the copy of field. Do I have to use index or is there any other way to modify the value?


Solution

  • The short & direct answer: no, use the array index instead of the value

    So the above code becomes:

    package main
    
    import "fmt"
    
    type MyType struct {
        field string
    }
    
    func main() {
        var array [10]MyType
    
        for idx, _ := range array {
            array[idx].field = "foo"
        }
    
        for _, e := range array {
            fmt.Println(e.field)
            fmt.Println("--")
        }
    }