Lua - trying to protect against nil value comparison

schwim · 2019-03-25T16:40:15.686Z

Hi there guys,

I’m trying to improve upon some of the functions running on my server and I’m having an issue figuring out how to wrap this comparison inside a check that will protect against a nil value

-- Trying to protect against nil value errors
function GetDataStore(name, owner)
	if #DataStores ~= nil then
		for i=1, #DataStores[name], 1 do
			if DataStores[name][i].owner == owner then
				return DataStores[name][i]
			end
		end
	end
end

But I still get attempt to get length of a nil value (field ‘?’)

I’ve tried both

if #DataStores ~= nil then

and

if #DataStores[name] ~= nil then

but it doesn’t seem to matter which I use, the error persists. How do I stop the comparison attempt if it’s trying to work on a non-existent value?

PichotM · 2019-03-25T17:23:03.176Z

schwim:

DataStores

does this table exists ?

schwim · 2019-03-25T17:25:07.209Z

That’s exactly what I was hoping to check for with my additional if not nil check. How to I check for the existence of the table?

zirconium · 2019-03-25T17:25:41.070Z

if DataStores ~= nil then

-- or, preferred
if DataStores then

you’re doing a length operator (#) first

or, even

if DataStores and DataStores[name] then