执行：使用现有数组的类型和值定义多维数组？

Question

Is it possible to a)define b)initialize a new multidimensional array using an existing array, like in following code instead of var b [2][3]int, just saying something like var b [2]a ?
Using a's type whatever it is, instead of hardcoding it (which misses the point of using [...] for a).
And perhaps handling initialization=copying of values at the same time?

package main

func main () {
        a := [...]int{4,5,6}
        var b [2][3]int
        b[0],b[1] = a,a 
}

(I'm aware of ease and convenience of slices, but this question is about understanding arrays.)

Edit: can't believe I forgot about var b [2][len(a)]int, beginner's brain freeze. One line answer would be var b = [2][len(a)]int{a,a} . That's a type conversion, right?

Answer 1

The following code would also work. Both your example and mine do the same thing and neither should be much faster than the other.

Unless you use reflect to make a slice (not array) of your [3]int, it is impossible to not repeat [3]int in your new type. Even that is not possible in the current release. It is in tip and will be released in Go 1.1.

package main

import "fmt"

func main() {
    a := [...]int{4,5,6}
    var b = [2][3]int{a, a}
    fmt.Println(b)
}