Re: double dim'd arrays

[Rob Kendrick <rjek@...>]

On Fri, Jul 15, 2011 at 09:51:15AM -0400, Dave Collins wrote:
> I've got an array of rotating adverts, each one has a lineup of ads it will go through. So I made a double-dimensioned array.
> 
> So:
> 
> local ad_lineup ={}
> ad_lineup.ad1 ={}	-- ad 1 lineup (*)
> ad_lineup.ad1[1] = "CoolWhip"
> ad_lineup.ad1[2] = "ShreddedWheat"
> ad_lineup.ad1[3] = "Swiffer"
> 
> ad_lineup.ad2 ={}	-- ad 2 lineup (*)
> ad_lineup.ad2[1] = "ShreddedWheat"
> ad_lineup.ad2[2] = "Swiffer"
> ad_lineup.ad2[3] = "Yumos"
> ad_lineup.ad2[4] = "Concierge"
> ad_lineup.ad2[5] = "foo"
> 
> ad_lineup.ad3 ={} -- ad 3 lineup (*)
> ad_lineup.ad3[1] = "NeedHelp"
> 
> Something tells me there is a more appropriate way to do this. In particular, do I need to declare each ad lineup "column" as a table in its own right? (see (*) lines above)

Nothing is stopping you putting tables into tables: you can put any
value in a table as key or value except nil.  So, perhaps:

ad_lineup = { 
	{ "CoolWhip", "ShreddedWheat", "Swiffer" },
	{ "ShreddedWheat", "Swiffer", "Yumos", "Concierge", "foo" },
	{ "NeedHelp" }
}

ad_lineup[1][2] is "ShreddedWheat", and add_lineup[2][3] is "Yumos".

You can also add them after the fact:

ad_lineup[4] = { "Spatula", "Plinth", "Boing" }

Or a variation on how you're doing it at the moment:

ad_lineup[4] = { }
ad_lineup[4][1] = "Tentacle"
ad_lineup[4][2] = "Spoo"

etc.  Or, you could create some functions that create your data
structure for you, so you could express it like this:

AddToLineup(2, "Swiffer") or similar.  Lots of options.

B.