英文:
How to use arbitrary length sequences of values as map keys in Go?
问题
编辑：Jeremy Wall帮助我意识到我提出了一个比我打算的更具体的问题；这是一个更好的版本。
假设我想要表示一个表，将某种类型B的值与某种类型A的值序列关联起来，其中定义了相等性。在Go中，最好的方法是什么？
显然，对于表，我想要使用Go的映射，但是对于类型A的值序列，我可以使用什么？在Go中，切片不能用作映射的键；数组可以，但是数组的长度是其类型的一部分，而我希望能够使用在运行时确定的长度的序列。我可以（1）使用声明了最大长度的A数组，或者（2）使用A切片，将它们序列化为字符串以用作键（这种技术对Awk和Lua程序员来说很熟悉...）。除了我描述的这些方法之外，是否有更好的解决办法来解决Go的这个“特性”？
正如Jeremy Wall在回答我原始版本的问题时指出的那样，当A = int时，选项（2）对于整数来说非常好，因为您可以使用符文切片，将其转换为字符串只是一个强制转换。
英文:
Edit: Jeremy Wall helped me realize I had asked a question more specific than I intended; here's a better version.
Say I want to represent a table associating of values of some type B to sequences of values of some type A for which equality is defined. What is the best way to do that in Go?
Obviously for the table I'd want to use a Go map, but what can I use for the sequences of values of type A? Slices cannot be used as keys for maps in Go; arrays can, but the length of an array is a part of it's type and I'm interested in being able to use sequences of length determined at runtime. I could (1) use arrays of A declaring a maximum length for them or (2) use slices of A, serialize them to strings for use as keys (this technique is familiar to Awk and Lua programmers...). Is there a better work around for this "feature" of Go than the ones I've described?
As pointed out by Jeremy Wall in answer to my original version of the question, where I had A = int, option (2) is pretty good for integers, since you can use slices of runes for which conversion to string is just a cast.
答案1
得分: 1
你是否希望使用rune序列而不是整数？runes是uint32类型，将其转换为字符串只需进行强制类型转换：
package main
import "fmt"
type myKey struct {
seq []int
}
func main() {
m := make(map[string]string)
key := []rune{1, 2}
m[string(key)] = "foo"
fmt.Print("lookup: ", m[string(key)])
}
你可以在这里尝试运行这段代码：http://play.golang.org/p/Kct1dum8A0
英文:
Will a sequence of rune instead of integers work for you? runes are uint32 and the conversion to a string is just a cast:
package main
import "fmt"
type myKey struct {
seq []int
}
func main() {
m := make(map[string]string)
key := []rune{1, 2}
m[string(key)] = "foo"
fmt.Print("lookup: ", m[string(key)])
}
You can play with this code here: http://play.golang.org/p/Kct1dum8A0
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