Alex, Have you looked at the Symbol data type and verb s:? I've not used it, but it may do what you want.
Tom Arneson -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of bill lam Sent: Friday, February 19, 2010 04:49 To: [email protected] Subject: Re: [Jprogramming] String to Numbers (WAS: RE: [Jchat] Multiple cores) M$ Excel biff uses similar method to store strings inside a workbook into a global table (sst), text in a cell is encoded as an index to that sst, you may browse the tara source code for detail. The real M$ Excel is more efficient because it allows using hash lookup instead of pure dyad i. ven, 19 Feb 2010, Alex Rufon skribis: > I know I've been on this path before but how did you guys do the conversion from string to numbers (and vice versa) in APL? Can we replicated this in J? > > Right now, I'm doing this by making a global vector of unique strings I've encountered. > DICTIONARY_z_ =: < every a. > > search=: verb define > data=. , boxopen y. > DICTIONARY_z_=: ~. DICTIONARY_z_,data > DICTIONARY_z_ i. boxopen y. > ) > > NB. boxopen is defined as: > NB. boxopen=: <^:(L. = 0:) > > > NB. Sample string data > [data=. (;: 'aa c3 d5 ae af ax ac ee'),<'The answer is 42' > +--+--+--+--+--+--+--+--+----------------+ > |aa|c3|d5|ae|af|ax|ac|ee|The answer is 42| > +--+--+--+--+--+--+--+--+----------------+ > > NB. Test data is 2 dimensions > [testdata=. 8 3 $ data > +--+--+----------------+ > |aa|c3|d5 | > +--+--+----------------+ > |ae|af|ax | > +--+--+----------------+ > |ac|ee|The answer is 42| > +--+--+----------------+ > |aa|c3|d5 | > +--+--+----------------+ > |ae|af|ax | > +--+--+----------------+ > |ac|ee|The answer is 42| > +--+--+----------------+ > |aa|c3|d5 | > +--+--+----------------+ > |ae|af|ax | > +--+--+----------------+ > > NB. Numeric equivalent of the strings > [asnumbers=. search testdata > 265 257 258 > 266 267 268 > 269 263 264 > 265 257 258 > 266 267 268 > 269 263 264 > 265 257 258 > 266 267 268 > > NB. Check if the numbers convert to strings > asnumbers { DICTIONARY > +--+--+----------------+ > |aa|c3|d5 | > +--+--+----------------+ > |ae|af|ax | > +--+--+----------------+ > |ac|ee|The answer is 42| > +--+--+----------------+ > |aa|c3|d5 | > +--+--+----------------+ > |ae|af|ax | > +--+--+----------------+ > |ac|ee|The answer is 42| > +--+--+----------------+ > |aa|c3|d5 | > +--+--+----------------+ > |ae|af|ax | > +--+--+----------------+ > > NB. Switch the columns > DICTIONARY {~ 1 2 1 { "1 asnumbers > +--+----------------+--+ > |c3|d5 |c3| > +--+----------------+--+ > |af|ax |af| > +--+----------------+--+ > |ee|The answer is 42|ee| > +--+----------------+--+ > |c3|d5 |c3| > +--+----------------+--+ > |af|ax |af| > +--+----------------+--+ > |ee|The answer is 42|ee| > +--+----------------+--+ > |c3|d5 |c3| > +--+----------------+--+ > |af|ax |af| > +--+----------------+--+ > > NB. Only get rows that's equal to 'aa' in the first column > [akey=. search 'aa' > 265 > [arows=. akey = {. "1 asnumbers > 1 0 0 1 0 0 1 0 > DICTIONARY {~ arows # asnumbers > +--+--+--+ > |aa|c3|d5| > +--+--+--+ > |aa|c3|d5| > +--+--+--+ > |aa|c3|d5| > +--+--+--+ > > NB. Or simply > DICTIONARY {~ asnumbers #~ (search 'aa') = {. "1 asnumbers > +--+--+--+ > |aa|c3|d5| > +--+--+--+ > |aa|c3|d5| > +--+--+--+ > |aa|c3|d5| > +--+--+--+ > > As you can see, it works. But I'm curious if there is another (better?) was to do it. The only requirement is that the numbers generated can be processed to get the original strings. > > Thanks. > > r/Alex > > -----Original Message----- > [---=| TOFU protection by t-prot: 17 lines snipped |=---] -- regards, ==================================================== GPG key 1024D/4434BAB3 2008-08-24 gpg --keyserver subkeys.pgp.net --recv-keys 4434BAB3 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
