Help with nested tables

krachall · March 2022

Can someone point me in the right direction for using dictionary style tables as a database? I'm trying to organize data in tables that I can extract with some interative function (ipairs or a do loop) but I'm not sure how to set this all up.

Basically here's what I have

{NAME = "Item A", LENGTH = "25", WIDTH = "12", HEIGHT = "8", TYPE = "box"}
{NAME = "Item B", LENGTH = "11", WIDTH = "18", HEIGHT = "4", TYPE = "bag"}
{NAME = "Item C", LENGTH = "19", WIDTH = "11", HEIGHT = "2", TYPE = "bag"}
{NAME = "Item D", LENGTH = "12", WIDTH = "15", HEIGHT = "1", TYPE = "box"}
{NAME = "Item W", LENGTH = "20", WIDTH = "14", HEIGHT = "9", TYPE = "box"}

Then I want to able to cycle through each of these rows and pick out individual variables.

So maybe I want to add up all the WIDTH of everything that's a box. I'd need to iterate through each Item, check if it's TYPE = Box, and if it is, recall the WIDTH field.

Suggestios?

krachall · March 2022

Figured it out and it was far simpler than I expected.

Baertram · March 2022

local myTab = {
{NAME = "Item A", LENGTH = "25", WIDTH = "12", HEIGHT = "8", TYPE = "box"}
{NAME = "Item B", LENGTH = "11", WIDTH = "18", HEIGHT = "4", TYPE = "bag"}
{NAME = "Item C", LENGTH = "19", WIDTH = "11", HEIGHT = "2", TYPE = "bag"}
{NAME = "Item D", LENGTH = "12", WIDTH = "15", HEIGHT = "1", TYPE = "box"}
{NAME = "Item W", LENGTH = "20", WIDTH = "14", HEIGHT = "9", TYPE = "box"}
}
local totalWidth = 0
for idx, dataTab in ipairs(myTab) do
  if dataTab.TYPE == "box" then
     totalWidth = totalWidth  + dataTab.WIDTH
  end
end

krachall · March 2022

Baertram wrote: »

local myTab = {
{NAME = "Item A", LENGTH = "25", WIDTH = "12", HEIGHT = "8", TYPE = "box"}
{NAME = "Item B", LENGTH = "11", WIDTH = "18", HEIGHT = "4", TYPE = "bag"}
{NAME = "Item C", LENGTH = "19", WIDTH = "11", HEIGHT = "2", TYPE = "bag"}
{NAME = "Item D", LENGTH = "12", WIDTH = "15", HEIGHT = "1", TYPE = "box"}
{NAME = "Item W", LENGTH = "20", WIDTH = "14", HEIGHT = "9", TYPE = "box"}
}
local totalWidth = 0
for idx, dataTab in ipairs(myTab) do
  if dataTab.TYPE == "box" then
     totalWidth = totalWidth  + dataTab.WIDTH
  end
end

Thanks. That's what I figured out and it works great. Far simpler than I thought it would be.

Question though...what if you had a three-deep table? how do you extract that value? would it be Table1.table2variable.table3variable?

M0R_Gaming · March 2022

Ya, pretty much. Or using indexes:

local out = 0
for table1ind=1,#table1 do
    local table2 = table1[table1ind]
    for table2ind=1,#table2 do
        local table3 = table2[table2ind]
        for table3ind=1,#table1[ta]
            if table3[table3ind].TYPE == "box" then
                out = out + table3[table3ind].WIDTH
            end
        end
    end
end
d(out)

After writing that, that looks like a nightmare and its prob not optimized lol

Alternatively, for ipairs:

local out = 0
for i, table2 in ipairs(table1) do
    for j, table3 in ipairs(table2) do
        for k, table4 in ipairs(table3) do
            if table4.TYPE == "box" then
                out = out + table4.WIDTH
            end
        end
    end
end
d(out)

Baertram · March 2022

Check ZOs build in table functions helpers, they also provide stuff like "find entry where key == ... and return value, or iterate over with functionX ...

Maybe it could help here:
https://github.com/esoui/esoui/blob/master/esoui/libraries/utility/zo_tableutils.lua