Re: Lua Tables

[Pierre Chapuis <catwell@...>]

On 2012-01-17 15:29, Sandeep Ghai wrote:
> Hello Everyone,
> I am learning Lua starting from the basics. I am right now doing with
> 'Tables'.
> But I am stuck at some point. I have read upto the tables  having two
> columns. Can anybody help me in making table that has more than two 
> coulmns?
> like:
>
> *Sr.No     x        y       Constraint     force*
> 1            0        0         fixed
> -
> 2            0        120      free           sideway
> 3           120     120       free           twist
> 4           120      0        fixed             -
>
>
>
> I tried with Nested tables,but get nothing. Is nested table a good 
> option?
> Thank you in advance.

This is a matrix (2D table). The two canonical ways to store
matrices are row-major order:


{ {"Sr.No","x","y","Constraint","force"},
  {1,0,0,"fixed","-"},
  {2,0,120,"free","sideway"},
  {3,120,120,"free","twist"},
  {4,120,0,"fixed","-"} }

and column-major order:

{ {"Sr.No",1,2,3,4},
  {"x",0,0,120,120},
  {"y",0,120,120,0},
  {"Constraint","fixed","free","free","fixed"},
  {"force","-","sideway","twist","-"} }

In this case it may be better to denormalize though:

{
  {
    ["Sr.No"] = 1,
    x = 0,
    y = 0,
    Constraint = "fixed",
    force = "-",
  },
  {
    ["Sr.No"] = 2,
    x = 0,
    y = 120,
    Constraint = "free",
    force = "sideway",
  },
  -- and so on
}

--
Pierre CHapuis