英文:
How should I define an empty slice in Go?
问题
以下是要翻译的内容：
更准确地说，我似乎可以做这三件事中的任何一件。它们之间有什么区别吗？哪个是最好的，为什么？
var foo []intfoo := []int{}foo := make([]int, 0)
请注意，我只会返回翻译好的部分，不会回答关于翻译的问题。
英文:
Or more precisely, it seems like I could do any of these three things. Is there any difference between them? Which is the best and why?
var foo []intfoo := []int{}foo := make([]int, 0)
答案1
得分: 9
区别如下：
（1）变量初始化为切片的零值，即nil（foo == nil）。
（2）和（3）将非nil的切片赋值给变量（foo != nil）。切片的底层数组指针被设置为保留给0字节分配的地址。
以下几点对于这三个语句都成立：
- 切片的长度为零：
len(foo) == 0。 - 切片的容量为零：
cap(foo) == 0。 - 语句不会分配内存。
因为len、cap和append可以处理nil切片，所以（1）通常可以与（2）和（3）互换使用。
语句2和3是短变量声明。这些语句也可以写成带有初始化器的变量声明。
var foo = []int{}var foo = make([]int, 0)
所有这些选项在Go代码中都常见使用。
英文:
The difference is:
(1) The variable is initialized to the zero value for a slice, which is nil (foo == nil).
(2) and (3) assign non-nil slices to the variable (foo != nil). The slice's underlying array pointer is set to an address reserved for 0-byte allocations.
The following points are true for all three statements:
- The slice length is zero:
len(foo) == 0. - The slice capacity is zero:
cap(foo) == 0. - The statement does not allocate memory.
Because len, cap and append work with nil slices, (1) can often be used interchangeably with (2) and (3).
Statements 2 and 3 are short variable declarations. These statements can also be written as a variable declaration with an initializer.
var foo = []int{}var foo = make([]int, 0)
All of the options are used commonly in Go code.
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