GLua - Getting the difference between two tables

Question

Disclaimer: This is Glua (Lua used by Garry's Mod)

I just need to compare tables between them and return the difference, like if I was substrating them.

TableOne = {thing = "bob", 89 = 1, 654654 = {"hi"}} --Around 3k items like that
TableTwo = {thing = "bob", 654654 = "hi"} --Same, around 3k
    
function table.GetDifference(t1, t2)

   local diff = {}
    
      for k, dat in pairs(t1) do --Loop through the biggest table
    
         if(!table.HasValue(t2, t1[k])) then --Checking if t2 hasn't the value
    
            table.insert(diff, t1[k]) --Insert the value in the difference table
            print(t1[k]) 
    
         end
    
      end
    
   return diff
    
end
    
if table.Count(t1) != table.Count(t2) then --Check if amount is equal, in my use I don't need to check if they are exact.
    
   PrintTable(table.GetDifference(t1, t2)) --Print the difference.
    
end

My problem being that with only one of difference between the two tables, this returns me more than 200 items. The only item I added was a String. I tried many other functions like this one but they usually cause a stack overflow error because of the table's length.

Answer 1

Your problem is with this line

if(!table.HasValue(t2, t1[k])) then --Checking if t2 hasn't the value

Change it to this:

if(!table.HasValue(t2, k) or t1[k] != t2[k]) then --Checking if t2[k] matches

Right now what is happening is that you're looking at an entry like thing = "bob" and then you're looking to see whether t2 has "bob" as a key. And it doesn't. But neither did t1 so that shouldn't be regarded as a difference.