Create a map of string to List
GoGo Problem Overview
I'd like to create a map of string to container/list.List instances. Is this the correct way to go about it?
package main
import (
"fmt"
"container/list"
)
func main() {
x := make(map[string]*list.List)
x["key"] = list.New()
x["key"].PushBack("value")
fmt.Println(x["key"].Front().Value)
}
Go Solutions
Solution 1 - Go
Whenever I've wanted to use a List I've found that a slice was the right choice, eg
package main
import "fmt"
func main() {
x := make(map[string][]string)
x["key"] = append(x["key"], "value")
x["key"] = append(x["key"], "value1")
fmt.Println(x["key"][0])
fmt.Println(x["key"][1])
}
Solution 2 - Go
My favorite syntax for declaring a map of string to slice of string:
mapOfSlices := map[string][]string{
"first": {},
"second": []string{"one", "two", "three", "four", "five"},
"third": []string{"quarter", "half"},
}
Solution 3 - Go
there's nothing technically incorrect about what you've written, but you should define your own type around map[string]*list.List to avoid some pitfalls, like trying to call the .Front() method on a nil pointer. Or make it a map[string]list.List to avoid that situation. A list.List is just a pair of pointers and a length value; using a list.List pointer in your map just adds the extra case of a nil pointer on top of the case of an empty list. In either situation, you should define a new struct for this use case.
I would be inclined to write it like this: http://play.golang.org/p/yCTYdGVa5G