How to achieve nested TMaps?

[SgtFlexxx]

Hi all,

In my wave-based gamemode, I’m trying to figure out how to achieve something akin to nested TMaps. The reason I need this is because I have “Squads” which contains a dictionary of units with the number of that unit in the squad, and each squad has a value attached to it for spawning purposes. The layout of what it would look like is this:

Squads = {
		SquadSmall = {
			Grunt: 4, //UnitClass: How many of this unit is in this squad
			GruntMedium: 1,
		}: 5 , //SquadID: Value of Squad (for spawning purposes in wave-based gamemode)
		SquadGrunts = {
			Grunts: 6,
		}: 5,
		SquadMedium = {
			Grunt: 3,
			GruntMedium: 2
		}: 7,
		SquadHeavy = {
			GruntMedium: 4,
			GruntHeavy: 2,
		}: 10,
	}

I know nested containers within UE4/5 is not as straightforward, so how could I best achieve this?

[Gossy]

Hi,

It looks from your example that you’re using a Dictionary as the key for the another Dictionary, which would definitely be quite complicated. A simplification would be to move the SquadID into a structure alongside a Dictionary of units, which would look like:

Squads = {
	"SquadSmall": {
		SquadID = 5,
		Units = {
			"Grunt" : 4,
			"GruntMedium" : 1
		}
	},
	"SquadGrunts": {
		SquadID = 5,
		Units = {
			"Grunt" : 6
		}
	},
	"SquadMedium": {
		SquadID = 7,
		Units = {
			"Grunt" : 3,
			"GruntMedium" : 2
		}
	},
	"SquadHeavy": {
		SquadID = 10,
		Units = {
			"GruntMedium" : 4,
			"GruntHeavy" : 2
		}
	}
}

Which in C++ code would look like:

USTRUCT(BlueprintType)
struct FSquadEntry
{
	GENERATED_BODY()
public:

	//Value of Squad (for spawning purposes in wave-based gamemode)
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
		int32 SquadID;

	//Unit Class, Quantity
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
		TMap<FName, int32> Units;

	//Constructor to make example look nice
    FSquadEntry():SquadID(0){};
	FSquadEntry(int32 ID, TMap<FName, int32> InUnits):SquadID(ID), Units(InUnits){};
};

USTRUCT(BlueprintType)
struct FSquadList
{
	GENERATED_BODY()
public:

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
		TMap<FName, FSquadEntry> Squads;

	//Construct dictionary using example data
	FSquadList()
	{
		Squads.Emplace("SquadSmall",
			FSquadEntry(5, {
				{"Grunt",4},
				{"GruntMedium", 1}
			}));
		Squads.Emplace("SquadGrunts",
			FSquadEntry(5, {
				{"Grunt",6}
			}));
		Squads.Emplace("SquadMedium",
			FSquadEntry(7, {
				{"Grunt",3},
				{"GruntMedium", 2}
			}));
		Squads.Emplace("SquadHeavy",
			FSquadEntry(10, {
				{"GruntMedium",4},
				{"GruntHeavy", 2}
			}));
	}
};

Hope that helps!

[SgtFlexxx]

I forgot to come back here but I had my friend take a look at my code and suggest the same thing. It was really this simple.