初始化空切片的正确方法 [英] Correct way to initialize empty slice

问题描述

要声明一个空切片，大小不固定，这样做更好吗:

To declare an empty slice, with a non-fixed size, is it better to do:

mySlice1 := make([]int, 0)

或:

mySlice2 := []int{}

只是想知道哪个是正确的方法.

Just wondering which one is the correct way.

推荐答案

您给出的两个替代方案在语义上是相同的，但是使用 make([]int, 0) 将导致内部调用runtime.makeslice(Go 1.16).

The two alternative you gave are semantically identical, but using make([]int, 0) will result in an internal call to runtime.makeslice (Go 1.16).

您还可以选择将其保留为 nil 值:

You also have the option to leave it with a nil value:

var myslice []int

如 Golang.org 博客中所述:

nil 切片在功能上等同于零长度切片，即使它不指向任何内容.它的长度为零，可以附加到分配中.

a nil slice is functionally equivalent to a zero-length slice, even though it points to nothing. It has length zero and can be appended to, with allocation.

nil 切片将 json.Marshal() 转换为 "null" 而空切片将编组为 "[]"，正如@farwayer 指出的那样.

A nil slice will however json.Marshal() into "null" whereas an empty slice will marshal into "[]", as pointed out by @farwayer.

正如@ArmanOrdookhani 所指出的，上述选项都不会导致任何分配.

None of the above options will cause any allocation, as pointed out by @ArmanOrdookhani.

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