I am trying to figure out what ($~$) means -- when would it ever be useful?
Intuitively, it is an identity function for arrays with 0 or 1 dimension. For matrices, it gives a different result: ($~$) i. 2 3 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 For higher dimensional arrays it gets even more complicated. So.... if you do not mind me asking: what are you using this for? Thanks, -- Raul On Mon, Oct 31, 2011 at 5:19 AM, Linda Alvord <[email protected]> wrote: > As I've been getting caught up with J, I've found it is often useful to keep > going a little longer and sometimes you notice things you might not > otherwise see. > > r =: 1 2 3 4 > v =: 13 14 15 16 > > Actually r and v change places so: > > f=: 13 :'x # ($~ $) y' > f > [ # [: ($~ $) ] > > +/v f r > 150 > > Linda > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Dan T. Abell > Sent: Thursday, March 10, 2011 10:08 AM > To: Programming forum > Subject: Re: [Jprogramming] Newbie question about repetition... > > > On 10 Mar 2011, at 07:35, Raul Miller wrote: > >> On Thu, Mar 10, 2011 at 8:29 AM, Henry Rich <[email protected]> wrote: >>> repeats # values >> >> That is how I would approach this problem. > > and for part two of the question: > r # ($r)$v > > >> -- >> Raul >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm > > -- > Dan T. Abell :: dabell at txcorp dot com :: 303.444.2452 > Tech-X Corp., 5621 Arapahoe Ave, Ste A, Boulder CO 80303 > http://www.txcorp.com :: 303.748.6894/c 303.448.7756/fx > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
