英文:
Creating a slice of slice of interfaces in go
问题
我正在尝试创建一个函数，将map的所有key, value作为slice的slice返回，其中每个元组为{key, value}。
以下是代码：
func ReturnTuples(map_ map[interface{}]interface{}) [][]interface{} {
toReturn := [][]interface{}{}
...
但是在toReturn这一行我遇到了错误：
type [][]interface {} is not an expression
我应该如何声明一个接口的切片的切片？我认为这是唯一的方法。我尝试了没有括号的方式：
[][]interface{}
但这也不起作用。
我尝试在谷歌上搜索“golang slice of slice”，但只有很少的结果。例如，我只找到了如何创建一个由uint8组成的简单切片，即[][]uint8。
英文:
I'm trying to create a function that returns the all the key, value of a map as a slice of slice of tuples (where each tuple is {key, value})
Here's the code:
func ReturnTuples(map_ map[interface{}]interface{}) [][]interface{} {
toReturn := []([]interface{})
...
But I'm getting error for the toReturn line:
type [][]interface {} is not an expression
How should I declare a slice of slice of interfaces? I see this as the only way. I tried without parenthesis like:
[][]interface{}
but it won't work either.
I tried to search for 'golang slice of slice' on google but very few things appear. For example I've only found how to create a simple one made of uint8, which is: [][]uint8.
答案1
得分: 3
切片的元素类型是interface{}，因此需要额外添加一对花括号来创建复合字面量：[]interface{}{}。
如果是切片的切片：
toReturn := [][]interface{}{}
或者使用make()函数时，需要指定一个_类型_（而不是复合字面量）：
toReturn := make([][]interface{}, 0, len(map_))
英文:
The element type of the slice is interface{}, so a composite literal needs an additional pair of braces: []interface{}{}.
In case of slice of slices:
toReturn := [][]interface{}{}
Or when using make(), you specify a type (and not a composite literal):
toReturn := make([][]interface{}, 0, len(map_))
答案2
得分: 2
你正在创建一个实例，而不是定义一个类型，所以你需要额外的一对花括号来初始化变量：
toReturn := [][]interface{}{}
英文:
You're creating an instance, not defining a type, so you need an extra pair of curly braces to initialize the variable:
toReturn := [][]interface{}{}
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