How to check if a table contains an element in Lua?
Given your representation, your function is as efficient as can be done. Of course, as noted by others (and as practiced in languages older than Lua), the solution to your real problem is to change representation. When you have tables and you want sets, you turn tables into sets by using the set element as the key and true
as the value. +1 to interjay.
You can put the values as the table's keys. For example:
function addToSet(set, key)
set[key] = true
end
function removeFromSet(set, key)
set[key] = nil
end
function setContains(set, key)
return set[key] ~= nil
end
There's a more fully-featured example here.