Re: table iteration problem

[steve donovan <steve.j.donovan@...>]

On Tue, Oct 18, 2011 at 8:27 AM, Victor Young <littlehaker@gmail.com> wrote:
> I've considered this method before. It's useful, but when the table has many
> keys, it will be troublesome and easy to make mistakes. Thanks any way!

That's true, so let's see if there's a better notation

t = ordered {
  {a = 1},
  {b = 2},
  {c = 3}
}

function ordered (spec)
   local t = { _keys = {} }  -- our output table, containing keys array
   for i,pair in ipairs(spec) do
      local k,v = next(pair)
      t[k] = v
      t._keys[i] = k
   end
   return t
end

that is, you end up with {a=1,b=2,c=3,_keys={'a','b','c'}}

Note the trick with the next() function - gets the first key-value pair!

Now you can do

for _,key in ipairs(t._keys) do
   local value = t[key]
   ...
end

steve d.

steve d.