Hi Jose Mario! Can you/anyone please explain the name=: 'body' (1 :) syntax? I have never seen this before. Where is it documented?
It doesn't seem to work with verbs: v=: '^' (3 :) v 3 : (,'^') v 5 |syntax error: v | v 5 Thanks in advance > Date: Thu, 3 Dec 2009 19:29:12 -0800 > From: [email protected] > To: [email protected] > Subject: Re: [Jprogramming] newbie question > > >To pull out the even numbers. So filter takes a predicate and a > >collection basically. I was thinking > > You can define filter as an adverb explicitly, > > filter=. '#~ x &>' (1 :) > > (2&|) filter i.11 > 1 3 5 7 9 > or tacitly, > > filter=. &> (#~`) (`:6) > > (0=2&|) filter i.11 > 0 2 4 6 8 10 > > This version also deals with boxed lists: > > palindrome=. -: |. > > ]WORDS=. ;:'Yesterday dad did buy mom a madam reviver 4-rotor engine > racecar with a radar detector' > ┌─────────┬───┬───┬───┬───┬─┬─────┬───────┬─┬─┬─────┬──────┬───────┬────┬─┬─────┬────────┐ > │Yesterday│dad│did│buy│mom│a│madam│reviver│4│-│rotor│engine│racecar│with│a│radar│detector│ > └─────────┴───┴───┴───┴───┴─┴─────┴───────┴─┴─┴─────┴──────┴───────┴────┴─┴─────┴────────┘ > > palindrome filter WORDS > ┌───┬───┬───┬─┬─────┬───────┬─┬─┬─────┬───────┬─┬─────┐ > │dad│did│mom│a│madam│reviver│4│-│rotor│racecar│a│radar│ > └───┴───┴───┴─┴─────┴───────┴─┴─┴─────┴───────┴─┴─────┘ > > palindrome filter (;:'blessed are they that belive that they are > blessed');'palindrome';'rats live on no evil star' > ┌────────────────────────────────────────────────────┬─────────────────────────┐ > │┌───────┬───┬────┬────┬──────┬────┬────┬───┬───────┐│rats live on no evil > star│ > ││blessed│are│they│that│belive│that│they│are│blessed││ > │ > │└───────┴───┴────┴────┴──────┴────┴────┴───┴───────┘│ > │ > └────────────────────────────────────────────────────┴─────────────────────────┘ > > palindrome filter > #~ palindrome&> > > > > > > ________________________________ > From: Lau B. Jensen <[email protected]> > To: Programming forum <[email protected]> > Sent: Wed, December 2, 2009 6:28:08 AM > Subject: Re: [Jprogramming] newbie question > > > > W.Ch Lin wrote: > > Does J have filter function like clojure's ? > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > I definitely want to hear what the J crowd says, but just to be sure, in > Clojure you could say > > (filter #(zero? (rem % 2)) (range 1 11)) > > 2 4 6 8 10 > > To pull out the even numbers. So filter takes a predicate and a > collection basically. I was thinking > in J I'd to something like > > ,.((|~ & 2) 1 + i. 10) ;, 1 + i.10 > +--------------------+ > |1 0 1 0 1 0 1 0 1 0 | > +--------------------+ > |1 2 3 4 5 6 7 8 9 10| > +--------------------+ > > Where as you can see all even values get a 0 return from (|~ & 2), but > that leaves 2 questions > > 1) Is that how you would do it with J at all? > 2) Disregarding 1, how would you pick those 0 values out from the > original list 1 + i.10 ? > > Thanks > Lau > > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm _________________________________________________________________ View your other email accounts from your Hotmail inbox. Add them now. http://clk.atdmt.com/UKM/go/186394592/direct/01/ ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
