I simply asked something more than what Syreldar showed me, storing values in more than one table, because I need to include a lot of values, just to have the data as clear as possible. It's not a problem if anyone from you can't afford that last my request, your support was enought helpful for me anyway. I'll follow Syreldar's function like this way:
local table =
{
x1, x2, x3, ---table_1
y1, y2, y3 ---table_2
z1, z2, z3 ---table_3
etc...
}
Tne two-return in the function I posted was simply an example to show you what I meant, I wrote that it was obviously wrong, and the "range of values" was referred to the other users who replied to me with that solution, including range of values (e.g.: item.get_vnum() >= x1 and item.get_vnum() <= x2).
Don't worry, I know how to lua code just as you all do, I could not be expert as you, but I developed a lot of usefull systems and I know what I'm doing too. By the way, thank you all again, expecially to Syreldar.