Re: Predicting ipairs (Was: Lua 5.2 Length Operator)

[Coda Highland <chighland@...>]

On Mon, Apr 16, 2012 at 8:39 AM, Coda Highland <chighland@gmail.com> wrote:
>>> Am I correct that # is the size of the array part of a table?
>> No.
>
> Indeed. Specifically:
>
> "The length of a table t is defined to be any integer index n such
> that t[n] is not nil and t[n+1] is nil; moreover, if t[1] is nil, n
> can be zero. For a regular array, with non-nil values from 1 to a
> given n, its length is exactly that n, the index of its last value. If
> the array has "holes" (that is, nil values between other non-nil
> values), then #t can be any of the indices that directly precedes a
> nil value (that is, it may consider any such nil value as the end of
> the array)."
>
> In your example, 4 is valid because slot 4 is non-nil and slot 5 is
> nil. But it could also have been 2, because slot 2 is non-nil and slot
> 3 is nil. Practically speaking you can only rely on the value of # for
> dense arrays.
>
> /s/ Adam

*jabs mail client* My apologies; I didn't see that someone else had
posted this already.

/s/ Adam