My test case was too small, removing the @ doesn't help (doesn't hurt too much either):
bv=: ?1000000$10000000 ts '~. (#~ -.@~:) bv' 0.051962 1.78282e7 bv=: ?1000000$10000000 ts '~.@(#~ -.@~:) bv' 0.051143 1.78285e7 On Sun, Jan 14, 2018 at 1:50 PM, Jimmy Gauvin <[email protected]> wrote: > You might try : > > ~. (#~ -.@~:) 4 6 8 6 5 8 6 6 6 9 > > 6 8 > > On Sun, Jan 14, 2018 at 1:09 PM, Skip Cave <[email protected]> > wrote: > >> Nice! Thanks to Henery Rich & R.E. Boss. >> >> For me, I want to list the dups just once. So I made this "find duplicates >> (and list them once)" verb: >> >> fdp=. ~.@(#~-.@~:) >> >> Works great! >> >> I had tried this: >> >> ~.a#~1<+/ e. a=. 4 6 8 6 5 8 6 6 6 9 >> >> 6 8 >> >> >> But my scheme doesn't scale well. I get "out of memory" errors on large >> lists, so it is very wasteful of space, and it is WAY slower. >> >> >> a=. ?1000$5000 >> >> (/:~fdp a) -: (/:~ ~.a#~1<+/ e. a) >> >> 1 >> >> ts 'fdp a' >> >> 5.99449e_6 4224 >> >> ts '~.a#~1<+/ e. a' >> >> 0.00294153 1.07405e6 >> >> >> >> >> Skip >> >> >> >> >> >> >> Skip Cave >> Cave Consulting LLC >> >> On Sun, Jan 14, 2018 at 10:44 AM, R.E. Boss <[email protected]> wrote: >> >> > (-.@~:)4 6 8 6 5 8 6 6 6 9 >> > 0 0 0 1 0 1 1 1 1 0 >> > >> > >> > R.E. Boss >> > >> > >> > > -----Original Message----- >> > > From: Programming [mailto:[email protected]] >> > > On Behalf Of Skip Cave >> > > Sent: zondag 14 januari 2018 17:34 >> > > To: [email protected] >> > > Subject: [Jprogramming] Finding duplicates >> > > >> > > I have a string of integers. How do I list just the duplicates in the >> > string? >> > > >> > > Skip >> > > ------------------------------------------------------------ >> ---------- >> > > For information about J forums see http://www.jsoftware.com/forum >> s.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
