go - 尝试使用追加删除字符串数组中的连续项目

Question

我无法理解以下结果。我期待代码

package main
import "fmt"

func main() {
    fruits := []string{"apple", "banana", "orange", "kiwi", "ananas"}
    for i, _ := range fruits {
        s := append(fruits[:i], fruits[i+1:]...)
        fmt.Println(s)
    }
}

返回:

[banana orange kiwi ananas]
[apple orange kiwi ananas]
[apple banana kiwi ananas]
[apple banana orange ananas]
[apple banana orange kiwi]

相反，它返回:

[banana orange kiwi ananas]
[banana kiwi ananas ananas]
[banana kiwi ananas ananas]
[banana kiwi ananas ananas]
[banana kiwi ananas ananas]

我错过了什么？注意:我注意到正在寻找返回预期行为的代码，只是想了解代码的作用。 Playground :https://play.golang.org/p/CB73GYvY7aW

Answer 1

正如规范所说:

The append built-in function appends elements to the end of a slice. If it has sufficient capacity, the destination is resliced to accommodate the new elements. If it does not, a new underlying array will be allocated. Append returns the updated slice.

在你的例子中，底层 slice 总是足够的，所以它每次都会修改它。根据规范，结果是可以预期的。

每个循环的s/fruit:

[banana orange kiwi ananas] [banana orange kiwi ananas ananas]
[banana kiwi ananas ananas] [banana kiwi ananas ananas ananas]
[banana kiwi ananas ananas] [banana kiwi ananas ananas ananas]
[banana kiwi ananas ananas] [banana kiwi ananas ananas ananas]
[banana kiwi ananas ananas] [banana kiwi ananas ananas ananas]