Why does this no longer work,it has always worked before?

local test = {}
test["hi"] = "lol"
print(#test)

I am very confused to why it prints 0. Did roblox change something?

You can't get the length of a dictionary, only an array with ascending numbers as index's.

local Array = {}

for i = 1, 3 do
	Array[i] = 'hi'
end

print(#Array)

OUTPUT:

3