Need Help (Array of strings)

Development Programming & Scripting C++
1

Hey guys!

I have an array of strings (4 in the array) which acts as names for drug ingredients for a drug system I’m working on.
The drug system uses labs which holds up to 5 ingredients to mix at once. I need to check to see if the combination matches one that I give it.

For example:
I’m trying to see if the drug lab has the following ingredients with no duplicates.

“Coca leaves”, “Trimethylpentane”, “Ammonia” and “Sulfuric Acid”.

How can I do this, again… checking the names against the strings in the array.

–

Disclaimer: This isn’t a system for an OOL, so unfortunately I can’t use Objects otherwise I would.

Any help would be greatly appreciated.

2

Just compare the contents of the array?

I’m not at home, so this function isn’t mine - just added a small quick fix:

Just check this thread, might help you:

I hope this is what you’re asking for - although for UE4 arrays this might not be suitable, better check the documentation.

3

So you have a string array that contains your recipe, like “Ingredient A”, “Ingredient B”, “Ingredient C”.
Then you have a variable string array that you want to check whether it is the same as the recipe, but:

  • the order doesn’t matter
  • duplicates are not allowed
  • are extras allowed?

One simple method I can think of is this:

  • Make a copy of the variable string array, lets call it ContentsCopy.
  • Iterate over all strings ‘IngredientName’ in the recipe array, call ContentsCopy.RemoveSingle(IngredientName). If RemoveSingle returned 0, the ingredient was not present, meaning the check failed. We’re done, abort.
  • After iterating if RemoveSingle never returned 0, check if ContentsCopy is empty. If it is, then the contents exactly matched your recipe.

RemoveSingle documentation: TArray::RemoveSingle | Unreal Engine Documentation

4

I’ll offer an alternative to the string check (not sure if it’s valid or not).

Rather than doing string compares against 4 other strings, I’d simply sort the ingredients, append them into one large string, and then just hash that string to get a simple uint32 that could be used as a key into a map that contains all the valid recipes.

e.g.



TMap<uint32, FString> HashToRecipeMap; // All known recipes and their incredients.

// Load up all valid recipes.
void InitializeRecipeMap()
{
   // For each Recipe you have, do the following:
   FString RecipeName = "Some Recipe";
   // Read in the incredients into a TArray<FString>.
   TArray<FString> Ingredients;
   
   HashToRecipeMap[GetRecipeHash(Ingredients)] = RecipeName;
   
}

// Create a hash based on the ingredients passed in.
void GetRecipeHash(const TArray<FString>& ingredients) const
{
	// You could possibly move this sort outside of the function, just depends on who you want to be responsible for the sort.
	TArray<FString> SortedArray(ingredients);
	SortedArray.Sort();
	
	FString hashString;
	
	// Build up a string that is just all the ingredients concatentated together alphabetically.
	for each (FString ingredient in SortedArray)
	{
	  hashString.Append(ingredient);
	}
	
	return GetTypeHash(hashString);
}

// Check to see if we can make something with the ingredients selected.
bool IsValidRecipe(const TArray<FString>& ingredients) const
{
	return HashToRecipeMap.Contains(GetRecipeHash(ingredients));
}