How to dynamically create a TMap

Development Programming & Scripting
,
1

I have a function that is meant to create and return a new TMap. However, I’m not sure how to dynamically create a new TMap. I tried NewObject<TMap<FString, FString>>(), but that gives me a compile error.
I can do it using “new”, but I understand that this will make it not work with Garbage Collection.
What is the proper way to do this.
Thanks

2

TMap isnt a UObject,

just create a variable
TMap<FString, FString> MapName;

3

Thanks. The problem is that I need to create a TMap inside a function and return a pointer to it. If I just create is as a stack variable, it’ll get destroyed when the function exits and this gives me a compiler error to the effect that I can’t return a local variable pointer. I really need to create it on the heap to ensure it persists beyond the function lifetime, so normally, I would need to use “new TMap<…>”. But does that mean that I have to take care of destroying it manually later, or does TMap have some built in GC behavior. Alternately, should I put it inside a TSharedPtr instead, which will destroy it when there are no more references to it?

4

I have something like this that seems to work. Hopefully it can help you.

Header:

static TMap<ECharacterPose, float> AddMap(TMap<ECharacterPose, float> Sums,
	                                          const TMap<ECharacterPose, float>& Addends);

CPP:

TMap<ECharacterPose, float> AGameModeArsenal::AddMap(TMap<ECharacterPose, float> Sums,
                                                     const TMap<ECharacterPose, float>& Addends)
{
	for (const auto& Addend : Addends)
	{
		if (Sums.Find(Addend.Key))
		{
			Sums[Addend.Key] += Addend.Value;
			continue;
		}

		Sums.Emplace(Addend.Key, Addend.Value);
	}

	return Sums;
}

Called from a void non-static method:

Multi->AdsSpeeds = AddMap(Multi->AdsSpeeds, Raw->AdsSpeeds);
1 Like