Oh, or
}.~ [: i.&1 ~:&0
That should be really fast.

Marshal

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of gary ng
Sent: Sunday, August 29, 2010 7:55 PM
To: Programming forum
Subject: Re: [Jprogramming] Splitting an integer into its digits

On Sun, Aug 29, 2010 at 11:49 AM, Alex Gian <[email protected]>
wrote:
> Thanks for the tip about the precomputed values, I should have done it 
> to be fair, since I use it in my Perl comparison, but I forgot as I'm 
> concentrating on learning J here...  It does indeed bring a big 
> speedup, although I'm pretty sure that my integer-splitting method is 
> a quite a bit faster than the one you suggest.
>
> I like the idea of using rank 1 rather than transpose.
>
> Anyway, fastest I've got so far, and quite an acceptable result to me 
> would now be specialX -. = +/"1@({&f)@(10&#.inv) if only I could sort 
> out the leading zero problem.  Your

not sure if this is an efficient way to do a 'dropWhile (=0)'

(#~[:>&0+/\) 0 1 2 3
=> 1 2 3
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