[go-nuts] slice: copy to zero length slice

[高橋誠二]

As official doc explains, copy to zero length slice results to be empty.

package main

import "fmt"

func main() {
    src := []int{1, 2, 3}
    dst := []int{}
    fmt.Println(len(dst))
    copy(dst, src)
    fmt.Println(src)
    fmt.Println(dst)
    // [1 2 3]
    // []

    src2 := []int{1, 2, 3}
    dst2 := make([]int, len(src))
    copy(dst2, src2)
    fmt.Println(src2)
    fmt.Println(dst2)
    // [1 2 3]
    // [1 2 3]
}



But it seems unusual, is it should be like following?

package main

import "fmt"

func main() {
    src := []int{1, 2, 3}
    dst := []int{}
    fmt.Println(len(dst))
    copy(dst, src)
    fmt.Println(src)
    fmt.Println(dst)
    // [1 2 3]
    // [1 2 3]
}


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