How to do custom Sorting in a List?

Unity Engine
,
1

I have a ScriptableObject in unity

[CreateAssetMenu(fileName = "New Food", menuName = "Prismalia/ScriptableObject/Food")]
public class FoodScriptableObject : ScriptableObject, IComparable
{
[Header("Basic Info")]
public string itemID;
public new string name;

[Header("Main food stats")]
public string MainEffect;
public int MainEffectValue;
public bool MainValuePercent = false;
public int Amount;

[Header("Sub food stats")]
public string SubEffect;
public int SubEffectValue;
public bool SubValuePercent = false;

public string Description;

[Header("Enums")]
public Rarity Rarity;
public FoodType FoodType;
public MainFoodEffect MainFoodEffect;
public FoodEffectsTypes MainFoodEffectType;
public SubFoodEffect SubFoodEffect;
public FoodEffectsTypes SubFoodEffectType;

[Header("Visuals")]
public Sprite MainSprite;
public Sprite SubSprite;
public GameObject Prefab;

[Header("Arrays")]
public string[ ] RefinementRankDescription;

public int CompareTo(object obj)
{
var a = this;
var b = obj as FoodScriptableObject;

if (a.Amount < b.Amount)
return -1;

if (a.Amount > b.Amount)
return 1;

return 0;
}

}

I save a lot of them in a list on a other Scriptnd here I sort it based on the amount

if(bSort)
{
scripts.Sort();
}

How can I make it sort acd and dec? based on the amount and how can I make it sort from a diffren variable or an enum for intance sort by rarity?

public enum Rarity
{
Common,
Uncommon,
Rare,
Epic,
Legendary,
Mythic
}

If any one helps please try not to use lamda typing as I dont understand lamda

I tried making a new list and coping it over to it as I have multiple scriptable objects and I save all in a normal List and get the type by GetType() then use the values

2

Various flavors of array and list sort have overloads that can take a keying or comparison predicate.

If you post a code snippet, ALWAYS USE CODE TAGS:

How to use code tags: Using code tags properly

3

Managed to sort it based on rarity but idk if it is really optimised

bSort = false;
List obj = new List();
for (int i = 0;i < scripts.Count;i++)
{
obj.Add((FoodScriptableObject)scripts*);*
}
var sortedList = obj.OrderByDescending(x => (int)(x.Rarity)).ToList();
scripts.Clear();
for (int i = 0; i < sortedList.Count;i++)
{
scripts.Add(sortedList*);*
}

4

You can do it in just one line:

scripts = scripts.OrderByDescending(x => x.Rarity).ToList();

For performance, it should be ok, as long as you donā€™t have thousands of items in the list or youā€™re not running it 100 times per frameā€¦

5

Youā€™re still not using code tagsā€¦ use code tags:

Also in your code youā€™re using linq to order the list and then generating a whole new list. Does it work? Yes. Is it the best way to go about it? Not particularly since youā€™re literally generating a whole new list.

As Nad_B pointed out it youā€™re not doing this often it may not matter. But if you do become concerned about itā€¦ as Kurt said list and arrayā€™s sort methods have overloads for sorting custom wise.

Here is the documentation for List.Sort (it appears ā€˜scriptsā€™ in this case are in a List):

The documentation includes examples.

In your case something like:

lst.Sort((a, b) => a.Rarity.CompareTo(b.Rarity));

sort ascending by rarity

lst.Sort((a, b) => b.Rarity.CompareTo(a.Rarity));
//or
lst.Sort((a, b) => -a.Rarity.CompareTo(b.Rarity));

sorts descending by rarity

This will sort your list in place rather than creating a new list.

(also note how much easier the code is to read in code tags)

5 Likes
6

Using SortedSet is another option:

SortedSet<FoodScriptableObject> foodsByAmount = new(new SortByAmount());
SortedSet<FoodScriptableObject> foodsByRarity = new(new SortByRarity());

private sealed class SortByAmount : IComparer<FoodScriptableObject>
{
    public int Compare(FoodScriptableObject a, FoodScriptableObject b) => a.Amount.CompareTo(b.Amount);
}

private sealed class SortByRarity : IComparer<FoodScriptableObject>
{
    public int Compare(FoodScriptableObject a, FoodScriptableObject b) => a.Rarity.CompareTo(b.Rarity);
}
1 Like
7

IComparers could also be used with normal lists:

private readonly SortByAmount _sortByAmount = new();
private readonly SortByRarity _sortByRarity = new();

// ...
list.Sort(_sortByAmount);
list.Sort(_sortByRarity);

BTW the C# compiler creates (and caches) under the hood an IComparer (Comparison) and uses it when using the .Sort(lambda) shown by @lordofduct

2 Likes