Thanks. Also, yeah I don't know why but I assumed it had to beatheist largest 9 digit prime. I guess because all the other PE problems with pandigitals was for the 1-9 or 0-9.
___________________________ David Vaughan On 8 Jul 2011, at 16:03, Ric Sherlock <[email protected]> wrote: > Let's forget tacit for now and just focus on the primitives > > 1 p: i.15 NB. dyadic p: with a left argument of 1 tests > for primality (see dictionary page for p:) > 0 0 1 1 0 1 0 1 0 0 0 1 0 1 0 > 1&p: i. 15 NB. the & conjunction just binds the left > argument to p: to create a new monadic verb (1&p:) > 0 0 1 1 0 1 0 1 0 0 0 1 0 1 0 > NB. You could assign a name to the new verb > isPrime=: 1&p: > NB. this can be convenient but is not necessary > (1 p: i. 15) # (i. 15) > 2 3 5 7 11 13 > (i. 15) #~ (1 p: i. 15) NB. the adverb Passive ( ~ ) swaps the > left and right arguments > 2 3 5 7 11 13 > NB. or if there is only a right argument > +~ 4 > 8 > In terms of the PE question, I think it might help to reread the > question to make sure you are clear on the potential answers. > > > On Sat, Jul 9, 2011 at 1:14 AM, David Vaughan > <[email protected]> wrote: >> I've found that method to be pretty simple in the end, using 10^i.9 >> Could you explain in: >> (#~ 1&p:) i. 50 >> What's going on, particularly the role of ~ as I find that adverb confusing. >> I know that p:y can be used to find the yth prime, but I don't understand >> why it tests for primes when 1& precedes it. >> Thanks. >> ___________________________ >> >> David Vaughan >> >> On 8 Jul 2011, at 12:38, Ric Sherlock <[email protected]> wrote: >> >>> Project Euler? >>> >>> To get the permutations in reverse order you could reverse the string >>> or reverse the list of permutation indicies. i.e. >>> 0 1 2 3 A. 'cba' >>> 3 2 1 0 A. 'abc' >>> >>> In J you are better off testing the whole array of permutations rather >>> than looping through them, so >>> (1&p: # ]) i. 50 >>> or >>> (#~ 1&p:) i. 50 >>> 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 >>> >>> On Fri, Jul 8, 2011 at 10:53 PM, David Vaughan >>> <[email protected]> wrote: >>>> I'm trying to find the highest 1-9 pandigital prime, so I need to get the >>>> permutations in reverse order if possible. Also, how can I apply my >>>> primeTest script to the results? >>>> >>>> primeTest =: 3 : 'if. #@:q:y do. y end. ' >>>> This is what I have so far. The rank of y and of the list of permutations >>>> don't match up, and it feels like my 'if.' approach isnt great. >>>> >>>> Can anyone offer any advice as to how achieve this? >>>> >>>> Thanks. >>>> >>>> ___________________________ >>>> >>>> David Vaughan >>>> >>>> On 8 Jul 2011, at 11:29, Ric Sherlock <[email protected]> wrote: >>>> >>>>> (i.@!@# A. ]) 'abcd' >>>>> or >>>>> (A.~ i.@!@#) 'abcd' >>>>> >>>>> see also: >>>>> http://rosettacode.org/wiki/Find_the_missing_permutation#J >>>>> >>>>> On Fri, Jul 8, 2011 at 9:44 PM, David Vaughan >>>>> <[email protected]> wrote: >>>>>> >>>>>> How would you go about getting all the permutations of a string in J? >>>>>> ___________________________ >>>>>> >>>>>> David Vaughan >>>>>> ---------------------------------------------------------------------- >>>>>> 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 >> ---------------------------------------------------------------------- >> 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
