Is there a way to linking two data values, simpler than Dictionary?

Question

I'm working on a game with Unity in which the player has some spells. I have an enum that contains all of these and I want to attach them a bool value. I think I can use a System.Collections.Generics.Dictionary with the Spells as Keys and the Boolean as Value, but is there a simpler way to do such a thing?

Why is a dictionary not simple enough for you? Please provide at least some usage examples. — dymanoid, Feb 28 '20 at 12:41
if `enum` is a simple one (i.e. starts from `0`), e.g. `public enum MyEnum {Fireball, Levitate, ...}` you can try *array* : `bool[] hasSpells = ...` `if (hasSpells[(int)spell]) {...}` — Dmitry Bychenko, Feb 28 '20 at 12:42
Not to offend or be rude, but I think Dictionaries are actually relatively simple data structures. You have a key and an associated value, that's basically it. If you're having trouble with Dictionaries, I'd recommend you start off by doing some "classical" programming exercises and challenges before you attempt writing a fully fledged game, even in such a feature rich game engine like Unity — MindSwipe, Feb 28 '20 at 12:43
If your enum is a bitmask then you can use a single value to indicate all of the available enum values for the user. Some info here: https://stackoverflow.com/questions/3261451/using-a-bitmask-in-c-sharp — David, Feb 28 '20 at 12:45
Yes, dictionnary are simple collections but it's not really what I expect. I want something just to say "this value from the enum is true, this one is false". — , Feb 28 '20 at 12:46
@AnoopRDesai what would happen when there are 10 enum values, 5 of which have been assigned to 0 and 5 assigned to 1? — ColinM, Feb 28 '20 at 13:24
@ColinM Yes, my bad, I missed that somehow :) Will delete my comment. — Anoop R Desai, Feb 28 '20 at 15:38

Dmitry Bychenko · Accepted Answer · 2020-02-28T13:10:18.793

3

You can simplify Dictionary<Spell, bool> hasSpell into HashSet<Spell> (you want only Key, not Value from the initial Dictionary):

  public enum Spell { 
    Fireball,
    Levitate,
    Resurrect,   
  };

  ...

  HashSet<Spell> abilities = new HashSet<Spell>() { 
    Spell.Fireball, 
    Fireball.Levitate,
  };

  ...

  // If the hero can resurrect...
  if (abilities.Contains(Spell.Resurrect)) {
    // ...let him raises from the dead
  }

edited Feb 28 '20 at 13:10

answered Feb 28 '20 at 12:46

Dmitry Bychenko

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This is not exactly what I wanted, but well, it works. It's so simple I didn't think about it. – Feb 28 '20 at 13:09

score 0 · Answer 2 · answered Feb 28 '20 at 18:44

Individually the simplest way of pairing two data values is to use a value tuple. This feature can be used on any Unity version from 2018.3 onwards as that's when it stopped using outdated C# versions.

var spell = ("Fireball", true);

If you'd rather be more explicit about types:

(string, bool) spell = ("Fireball", true);

score 0 · Answer 3 · answered Mar 05 '20 at 00:10

(This is another approach in making things "easy")

Yes, dictionnary are simple collections but it's not really what I expect. I want something just to say "this value from the enum is true, this one is false"

This sounds you need a nice class that encapsulates the less-simple or more low-level structure (e.g. dictionary or hashset). This will things easy from the outside / API-isde.

For example:

public enum Spell
{
    Firebolt,
    Rage,
    Flash,
};


public class SpellState
{
    private HashSet<Spell> _enabled = new HashSet<Spell>();

    public void EnableSpell(Spell spell)
    {
        _enabled.Add(spell);
    }

    public void DisableSpell(Spell spell)
    {
         _enabled.Remove(spell);
    }

    public bool IsSpellEnabled(Spell spell)
    {
        return _enabled.Contains(spell);
    }
}

Usage

var spellState = new SpellState();

spellState.EnableSpell(Spell.Rage);

// later
if (spellState.IsSpellEnabled(Spell.Flash))
{
    spellState.DisableSpell(Spell.Rage);
    // todo
}

score 0 · Answer 4 · answered Mar 05 '20 at 00:34

0

You could use a single bitwise value by defining enum flags, so long as you have a limited number of spells.

[Flags]
public enum Spell : long
{
    Firebolt = (1 << 0),
    Rage = (1 << 1),
    Flash = (1 << 2),
};

answered Mar 05 '20 at 00:34

Jeremy Lakeman

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Is there a way to linking two data values, simpler than Dictionary?

4 Answers4