I would have expected this code to work:
package main
type Item struct {
Key string
Value string
}
type Blah struct {
Values []Item
}
func main() {
var list = [...]Item {
Item {
Key : "Hello1",
Value : "World1",
},
Item {
Key : "Hello1",
Value : "World1",
},
}
_ = Blah {
Values : &list,
}
}
I thought this would be the correct way of doing this; Values is a slice, list is an array. &list should be a slice, which is assignable to Item[], right?
...but instead, it errors with the message:
cannot use &list (type *[2]Item) as type []Item in assignment
In C, you'd write:
struct Item {
char *key;
char *value;
};
struct Blah {
struct Item *values;
};
How do you do that in Go?
I saw this question: Using a pointer to array
...but either the answers are for a previous version of Go, or they're just plain wrong. :/
A slice is not simply a pointer to an array, it has an internal representation which contains its length and capacity.
If you want to get a slice from list you can do:
_ = Blah {
Values : list[:],
}
Go is, fortunately, not so verbose as it might seem from the OP. This works:
package main
type Item struct {
Key, Value string
}
type Blah struct {
Values []Item
}
func main() {
list := []Item{
{"Hello1", "World1"},
{"Hello2", "World2"},
}
_ = Blah{list[:]}
}
(Also here)
PS: Let me suggest to not write C in Go.
When you are starting out with Go ignore arrays completely and just use slices is my advice. Arrays are rarely used and cause Go beginners a lot of trouble. If you have a slice then you don't need a pointer to it since it is a reference type.
Here is your example with a slice and no pointers which is much more idiomatic.
package main
type Item struct {
Key string
Value string
}
type Blah struct {
Values []Item
}
func main() {
var list = []Item{
Item{
Key: "Hello1",
Value: "World1",
},
Item{
Key: "Hello1",
Value: "World1",
},
}
_ = Blah{
Values: list,
}
}