Accessing a map using its reference

Question

I try to loop through a map, that I pass as a pointer to a function, but I can\'t find a way to access the elements. This is the code:

func refreshSession(sessio         


        

Answer 1

You don't need to use a pointer with a map.

Map types are reference types, like pointers or slices

If you needed to change the Session you could use a pointer:

map[string]*Session

Answer 2

You are not taking into account the precedence of *.

*session[sid] really means *(session[sid]), that is, first indexing the pointer to map (hence the error), then dereferencing it.

You should use (*session)[sid].timestamp to first dereference the pointer to the map and then access it using the key.

Answer 3

De-reference the map first and then access it (Example on play):

(*sessions)[sid]

It's also noteworthy that maps are actually reference types and therefore there is a very limited use-case of using pointers. Just passing a map value to a function will not copy the content. Example on play.