LeftJoins with tables (removing values from tables)

[Clemens Wacha <clemens.wacha@...>]

Hello,

Very often I have collection of objects and I want to know which 
objects from both collections are in common or are only in one of 
them. 

For this I have created the following pseudo code function that 
subtracts one table from the other

-- subtracts all elements in table2 from table1
function( table1, table2)
 tmp = copy of table1
 
 for all objects in table1 do
  if there is one too in table2
   remove it from tmp
  end
 end
 return tmp
end

In lua I made a deep copy of the table and tried to achieve this 
using table.remove but this function sucks somehow. Since i am 
removing elements from a table the index changes inside the table 
and this prevents me from _efficiently_ finding the objects to 
remove. 

Now my question: Can I travel a table using for in Lua AND remove 
objects form the same table inside the for loop?

for key, value in table do
 if value == "object_to_delete" then
  table.remove(table, key)
 end
end

Thanks
-- 
Clemens Wacha             wacha@gmx.ch            ICQ:12620942

successfully using Linux since 1999. See http://www.debian.org