Confirming existence of a string in an xml table Lua

Question

Good afternoon everyone,

My problem is that I have 2 XML lists
<List1> <Agency>String</Agency> </List1>
and
<List2><Agency2>String</Agency2><List2>.
In Lua I need to create a program which is parsing this list and when the user inputs a matching string from List 1 or List 2, the program needs to actually confirm to the user if the string belongs to either L1 or L2 or if the string is inexistent. I'm new to Lua and to programming generally speaking and I would be very grateful for you answers. I have LuaExpat as a plugin but I can't seem to be able to actually read from file, I can only do some beginner tricks if the xml list is written in the code. At a later time this small program will be fed by an RSS.

Answer 1

require("lxp") 
local stuff = {} 

xmldata="<Top><A/> <B a='1'/> <B a='2'/><B a='3'/><C a='3'/></Top>" 

function doFunc(parser, name, attr) 
  if not (name == 'B') then return end 
  stuff[#stuff+1]= attr 
end 

local xml = lxp.new{StartElement = doFunc} 
xml:parse(xmldata) 
xml:close() 

print(stuff[3].a) 

This code is a tutorial over the web that works, everything is just fine it prints nr. 3. Now I want to know how to do that from an actual file, as if I input io.read:(file, "r" or "rb" ) under xmldata variable and run the same thing it returns either empty space or nil.