声明切片还是制作切片? [英] Declare slice or make slice?

问题描述

在 Go 中，var s []int 和 s := make([]int, 0) 有什么区别?

In Go, what is the difference between var s []int and s := make([]int, 0)?

我发现两者都有效，但哪个更好?

I find that both works, but which one is better?

推荐答案

除了 fabriziom 的 答案，您可以在Go Slices: usage and internals"，其中提到了 []int 的使用:

In addition to fabriziom's answer, you can see more examples at "Go Slices: usage and internals", where a use for []int is mentioned:

由于切片的零值 (nil) 的作用类似于零长度切片，您可以声明一个切片变量，然后在循环中附加到它:

Since the zero value of a slice (nil) acts like a zero-length slice, you can declare a slice variable and then append to it in a loop:

// Filter returns a new slice holding only
// the elements of s that satisfy f()
func Filter(s []int, fn func(int) bool) []int {
    var p []int // == nil
    for _, v := range s {
        if fn(v) {
            p = append(p, v)
        }
    }
    return p
}

这意味着，要附加到切片，您不必先分配内存:nil 切片 p int[] 作为一个切片就足够了添加到.

It means that, to append to a slice, you don't have to allocate memory first: the nil slice p int[] is enough as a slice to add to.

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