Oops, I said (-: /:) when I should have said (-:/:~)@, (And, (-:/:~)@,"0 for comparing individual boxed strings.)
Very, very different concepts. I hope I did not confuse anyone there, but I probably did. -- Raul On Sat, Dec 10, 2022 at 3:18 PM Raul Miller <[email protected]> wrote: > > Comparing strings is different from comparing characters. > > One approach would be to compare boxed strings -- this would require > using the (-: /:) mechanism. Or, perhaps (-: /:)"0 depending on the > desired result. > > Another approach would compare character lists. This would require > they be the same length. Here, you could use the <&(3&u:) mechanism > but it would fail on unequal length strings (just as < would fail on > unequal length number lists). > > Anyways, ... unicode gets into some "interesting territory" when > talking about ordering of "characters": > > B0=: {.B1=: 7 u: B2=: 'β' > B0 > β > B1 > β > B2 > β > B0 >&(3&u:) B1 > 0 > B0 >&(3&u:) B2 > 1 1 > > It's really simple. > > Except, when it's not. > > -- > Raul > > On Sat, Dec 10, 2022 at 2:49 PM Devon McCormick <[email protected]> wrote: > > > > 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 <[email protected]> > > 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> > > > 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 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
