声明数组大小是否明确确定按值传递还是按引用传递？

Question

以不改变其父数组的数组副本为例：

    a1 := [5]string{"English", "Japanese", "Spanish", "French", "Hindi"}
    a2 := a1 
    fmt.Println("a1 = ", a1) //[English Japanese Spanish French Hindi]
    fmt.Println("a2 = ", a2) //[English Japanese Spanish French Hindi]
    a2[1] = "German"
    fmt.Println("now a2 = ", a2) // [English German Spanish French Hindi]
    fmt.Println("and a1 = ", a1) // [English Japanese Spanish French Hindi]

不足为奇，a2 是副本，不是参考。更改一个副本不应更改另一个副本，它们保存在不同的地址。

现在看看如果我们不为 a1 声明大小会发生什么：

    a1 := []string{"English", "Japanese", "Spanish", "French", "Hindi"} // <--difference here
    a2 := a1
    fmt.Println("a1 = ", a1) //[English Japanese Spanish French Hindi]
    fmt.Println("a2 = ", a2) //[English Japanese Spanish French Hindi]
    a2[1] = "German"
    fmt.Println("now a2 = ", a2) // [English German Spanish French Hindi]
    fmt.Println("and a1 = ", a1) // [English German Spanish French Hindi]

当 a2 改变时，两者都会改变？！所以，如果你不声明数组的大小，然后将它分配给某个东西，突然它是一个引用？为什么 a2 := a1 的行为会因另一个变量的声明方式而完全不同？我很困惑哈哈。

Answer 1

我强烈建议阅读 Go 博客 post Arrays, slices and strings - 然后再读一遍 - 它包含许多其他微妙的副作用。

它将显示幕后发生的事情以及切片类型的表示方式：

sliceHeader{
    Length:        0,
    Capacity:      0,
    ZerothElement: nil, // points to a fixed size array
}

以及变异操作如何影响多个切片值。

最终引述：

Arrays have their place—they are a good representation of a transformation matrix for instance—but their most common purpose in Go is to hold storage for a slice.

声明数组大小是否明确确定按值传递还是按引用传递？

Does declaring an array size explicitly determine pass by value vs reference?

arrays

pass-by-reference

go