[solved] iterating throw multiple levels of a table

jack0088 · March 2012

I have a Xml parser which gives me a really deep structured table - but each level is based on same structure

Attributes = {
     id = "main"
}
Name = "g"
ChildNodes = {
     [1] = {
          Attributes = { id = "FredFeuerstein" }
          Name = "g"
          ChildNodes = {
               [1] = {
                  Attributes = {
                      id = "ShapeOfFred"
                  }
                  Name = ""
                  ChildNodes = {}
               }
               [2] = {...}
          }
     }
     [2] = {
          Attributes = { id = "Lol" }
          Name = "..."
          ChildNodes = {...}
     }
}

As you can see it has this structure, which is nested within each ChildNodes={}

table = {
   Attributes = {}
   Name = ""
   ChildNodes = {...}
}

How can I iterate through all of the items and make a new table out of it, that look similar to this:

newTable = {
     main = {
          FredFeuerstein = {
               ShapeOfFred = { ... }
          }
          Lol = { ... }
     }
}

Basically I want to take the id from Attributes in each level of depth and if it has ChildNodes then subordinate them into the newly created node in my newTable. Do you understand how I mean this? I just want to iterate through the whole big table with all those depths (which can be a lot: at least 2 levels) and take out the id's.

I was able to iterate through 2 levels of depth, but not all... I didn't managed to get a recursive function.. I don't know why...

How can I do this in Lua? I tried a lot and googled for 2 days, but it seems that I'm to stupid at the moment for this task, so please help!

--cheers
jack0088

ndoss · March 2012

I'm not sure if I totally understand what you need, but would this work?

function processTable(t,out)
   if out == nil then out = {} end
   if t and t.Attributes and t.Attributes.id then
      out[t.Attributes.id] = t
      if t.ChildNodes then
         for i,child in ipairs(t.ChildNodes) do
            processTable(child,t)
         end
      end
   end
   return out
end
 
newTable = processTable(myTable)

Given this table:

myTable = {
   Attributes = { id = "main" },
   Name = "g",
   ChildNodes = {
      {
         Attributes = { id = "FredFeuerstein" },
         Name = "g",
         ChildNodes = {
            {
               Attributes = { id = "ShapeOfFred" },
               Name = "myname",
            }
         }
      },
      {
         Attributes = { id = "Lol" },
         Name = "...",
      }
   }
}

You'd be able to access ShapeOfFred's name like so:

print("======>", newTable.main.FredFeuerstein.ShapeOfFred.Name)

Here's the printout of newTable using inspect.lua:

<1>{
  main = <2>{
    Attributes = <img class="emoji" src="https://forum.giderosmobile.com/resources/emoji/heart.png" title="<3" alt="<3" height="20" />>{
      id = "main"
    },
    ChildNodes = <4>{ <5>{
        Attributes = <6>{
          id = "FredFeuerstein"
        },
        ChildNodes = <7>{ <8>{
            Attributes = <9>{
              id = "ShapeOfFred"
            },
            Name = "myname"
          } },
        Name = "g",
        ShapeOfFred = <table 8>
      }, <10>{
        Attributes = <11>{
          id = "Lol"
        },
        Name = "..."
      } },
    FredFeuerstein = <table 5>,
    Lol = <table 10>,
    Name = "g"
  }
}

jack0088 · March 2012

Can I have it somehow building the new table like:

main = {
          FredFeuerstein = {
               ShapeOfFred = { ... }
          }
          Lol = { ... }
     }

So only the id's get nested in each other and no other data from the original table?

PS:how did you get the self references into the table?
Thank you very much so far and sorry, for my lack of knowledge...

jack0088 · March 2012

Got it

thank you for your amazing recursive function!

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