Raul's expression "<&(3&u:)" made me think of the endless complications for character comparison once you include multi-byte representations as in Unicode. So this initial expression works fine but extending it beyond elements of a. leads to ambiguity. 'A' <&(3&u:) 'a' 1 a. i. 'Aa' NB. confirming the inequality 65 97 NB. (load "define-abbrev-table.el") NB. This allows me to enter special characters in emacs 'α' <&(3&u:) 'a' 0 0 'α' <&(3&u:) 'β' NB. So should we say alpha is only partially less than beta? 0 1 (<a.) i. &> 'α';'β' 206 177 206 178
On Sat, Dec 10, 2022 at 7:28 AM 'Mike Day' via Chat <c...@jsoftware.com> wrote: > Yes, my suggestion was an example of using /:~ to exploit J's inbuilt > ordering for a > simple, quick answer; but maybe > /:~ 'aA1.;' > (eg) isn't the order relation you require, so I agree with Raul. > > Mike > > Sent from my iPad > > > On 9 Dec 2022, at 19:22, Jimmy Gauvin <jimmy.gau...@gmail.com> wrote: > > > > Hi, > > > > the domain of < and others could be extended to include characters. > > > > Sorting with /: and \: implies there is an "order" relation between > > characters. > > > > > > J > > > >> On Fri, Dec 9, 2022 at 6:21 AM Donna Ydreos <dy...@sympatico.ca> wrote: > >> > >> The domain of < is numeric. You can create a function for letters with > >> reference to alphabetic order or some given order including say all ASCI > >> characters. > >> > >>>> On Dec 9, 2022, at 3:47 AM, Jimmy Gauvin <jimmy.gau...@gmail.com> > wrote: > >>> > >>> Hi all, > >>> > >>> testing character data for equality works fine but testing for relative > >>> order does not. > >>> > >>> 'a'<'v' > >>> > >>> |domain error > >>> > >>> | 'a' <'v' > >>> > >>> 'a'='v' > >>> > >>> 0 > >>> > >>> Is this explained somewhere ? > >>> > >>> Thanks, > >>> > >>> Jimmy > >>> ---------------------------------------------------------------------- > >>> 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 > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Devon McCormick, CFA Quantitative Consultant ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
