EMPTY defined as i.0 0 instead of '' for a good reason. The frontend will print a blank line for '' but will print nothing for i.0 0
Ср, 07 июн 2017, robert therriault написал(а): > One thing to remember is that empty is already defined as a verb > > empty > (i.0 0)"_ > > So if you overwrite this you may break some code if you have previously > relied on the existing verb definition. > > I think along the lines that Pascal mentioned that null could be similarly > defined as > > null NB. check that it is not already used > |value error: null > null=:(i.0)"_ > NULL NB. check that it is not already used - uppercase for global nouns > is a convention I like and is often seen in J code > |value error: NULL > NULL=:'' NB. I use this as the null string (same as what John suggested) > NULL-:null 2 NB. any argument produces NULL from null > 1 > > Hope this helps, > > Cheers, bob > > > On Jun 7, 2017, at 8:09 AM, 'Jon Hough' via Programming > > <[email protected]> wrote: > > > > > > I may be wrong in doing this, but I usually write > > empty=: '' > > to signify an empty list, array, matrix etc. > > > > > > On Jun 7, 2017, 23:59, at 23:59, Michael Rice <[email protected]> wrote: > >> Is there a special "noun" for an empty list? > >> > >> Creating one seems enigmatic. > >> > >> empty =: 1 2 > >> empty > >> 1 2 > >> empty =: }. empty > >> empty > >> 2 > >> empty =: }. empty > >> empty > >> > >> empty1 =: > >> |syntax error > >> | empty1=: > >> ---------------------------------------------------------------------- > >> 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 -- regards, ==================================================== GPG key 1024D/4434BAB3 2008-08-24 gpg --keyserver subkeys.pgp.net --recv-keys 4434BAB3 gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
