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

问题描述

要声明一个不固定大小的空片， 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{}

只是想知道哪种方法是正确的.

Just wondering which one is the correct way.

推荐答案

您提供的两个选择在语义上是相同的，但是使用make([]int, 0)会导致对 runtime.makeslice 的内部调用(转到1.14).

The two alternative you gave are semantically identical, but using make([]int, 0) will result in an internal call to runtime.makeslice (Go 1.14).

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切片在功能上等效于零长度切片，即使它没有指向任何内容.它的长度为零，可以附加分配.

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.

但是，如@farwayer所指出的，nil切片将json.Marshal()放入"null"，而空切片将封送到"[]".

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

如@ArmanOrdookhani所述，以上选项均不会导致任何分配.

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

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