Attempt to concatenate number with nil

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#1

im currently creating a datatstore system that saves a table and these errors are coming out. im currently using a modulescript for the savedata and getdata functions:

function module.saveData(plr: Player, dataStore: DataStore, keyAddition:string, dataToSave)
	local success, err = pcall(function()
		print(keyAddition.."<br>"..dataToSave)
		dataStore:SetAsync(plr.UserId..keyAddition, dataToSave)
	end)
	
	if success then
		print("Successfully saved Data.")
	else
		warn(err)
	end
end

function module.getData(plr: Player, dataStore: DataStore, key)
	local data = {}
	
	local success, err = pcall(function()
		data = dataStore:GetAsync(plr.UserId..key)
	end)

	if success and data ~= nil then
		return dataStore
	elseif not success then
		warn(err)
	else
		print("Player is new. Creating new Data")
	end
end

when i call these functions they print a warning:

ReplicatedStorage.Data/Tables:35: attempt to concatenate number with nil 
ReplicatedStorage.Data/Tables:20: attempt to concatenate string with table
#2

Please show the entire module script, I cannot tell which lines are erroring.

#3

thats basically the modulescript. the errors its reffering to are the

if not success then 
     warn(err)
end
#4

Concatenating is linking multiple sets of characters together into one. In Lua, you can only concatenate strings and numbers. You can concatenate two variables by joining them together with a ..

print(keyAddition.."<br>"..dataToSave)

Since dataToSave is a table, Roblox throws an error when you try to concatenate it. The second error “attempt to concatenate number with nil” is most likely a result of keyAddition not existing, therefore it returns nil.

#5

Ah, I’ve found the error, you can’t concatenate strings and tables together.

Try changing it to

print(keyAddition, dataToSave)

It prints the ‘keyAddition’ then the ‘dataToSave’ afterwards!

1 Like
#6

what about the GetData function?
it still prints ReplicatedStorage.Data/Tables:20: attempt to concatenate string with table

EDIT: i just found a fix for it and its just the data variable. i basically just changed it from local data = {} to local data

EDIT AGAIN: the fix did NOT work.

#7

bumping cause i still havent found a fix for the second error

#8

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