fastest way to maintain nested tables of counters?

[Tim Menzies <tim@...>]

is the following code the best way to handle auto-initialization of nested table cells to zero?

 function inc3(c,x,y,z) -- inc 3d to zero

   c[x] = c[x] or {}

   c[x][y] = c[x][y] or {}

   c[x][y][z] = c[x][y][z] or 0

   c[x][y][z] = c[x][y][z] + 1

end

i ask since this task is the core of  my naive bayes classifier. so it must be fast.

notes: the table index names won't be known till runtime, so you can auto-init the data with the right names as a pre-processor.

oh-  i've read the automagical table entry (http://lua-users.org/wiki/AutomagicTables) and i cant quite justify to myself that that approach is preferred to the above. 

but i'd like the advice of some Lua gurus!

ADVAthanxNCE

share and enjoy!

:-)

tim menzies