Accessing list element with put_in for lists of structs

Hi @collectivelysuperior, welcome to the forum!

I think you can do try something like this:

def mute(%{connected_players: connected_players} = game, %{id: player_id}) do
  players = Enum.map(connected_players, fn 
    {id: ^player_id, muted?: false} = player -> %{player | muted?: true}
    player -> player
end

%{game | connected_players: players}

I think finding a player by id is quite frequent. For example, when a player joins the game, you also want to make sure you won’t add him/her twice if already in the room.

So I often end up with having the connected_players list as a map, whose keys are ids. Would that be easier for you?

%Game{connected_players: %{"foo" => %Player{id: "foo", ...}}}

If you want to keep using put_in, you could do it like this (haven’t tested it, but should be fine):

def mute(%Game{} = game, %Player{id: id} = player) do
  put_in(game, [
     Access.key(:connected_players), 
     Access.filter(&match?(%{id: ^id}, &1)), 
     Access.key(:muted?)
  ], not player.muted?)
end

Three different ideas but all very valid. Thank you all!! I like qhwa’s idea of having the connected players a map, which would make accessing the players easier.. If I stick with the list, I think the solution by @thiagomajesk is elegant and maintainable, if I ever need to change other fields in the player struct as well. (I didn’t know you could do multiple pattern matches in an anonymous function, cool!!)