Re: userdata as table-key

[Philippe Lhoste <PhiLho@...>]

RLake@oxfam.org.pe wrote:
> table.getn() does not return the size of the table; it
> only concerns itself with entries whose keys are positive
> integers. (In fact, it is simply, in effect, an attribute
> of the table, and can be set to an arbitrary value with
> table.setn(), but if that hasn't been done table.getn()
> searches for the largest integer key.)

To be accurate (to avoid confusion for newbies...), if the n field of the table
hasn't been changed, table.getn() returns the largest integer key when counting
consecutive indexes from 1.
I feel this sentence can be better formulated...

In other words, the array part of a table only have consecutive positive integer keys
starting at 1. Any other positive integer key, if there is a gap, isn't seen as index
of the array.

Exemple:
> array = { [9]=1, [7]=5, [5]=12.3, [3]=0.25, [2]=-45.01, [1]=7 }
> print(table.getn(array))
3

Likewise, ipairs will interate only on 1, 2, and 3.
and a = { [2] = 1, [3] = 4 } isn't an array (not starting at 1).

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Philippe Lhoste (Paris -- France)
Professional programmer and amateur artist
http://jove.prohosting.com/~philho/ (outdated)
http://philho.multimania.com (in French, for files to download)
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