The design of *cut* comes from section K of *Rationalized APL*<http://www.jsoftware.com/papers/RationalizedAPL.htm>, written by Ken Iverson in 1983 at the height of his powers. In the original publication the description of *cut* was split with half on one page and the other half on the obverse. In order to understand it, I finally had to photocopy the two halves and paste them together onto a single page, and studied the single page.
On Tue, Oct 9, 2012 at 8:43 PM, Ian Clark <[email protected]> wrote: > Thank you everybody. That's turned the hay over in my mind. > > I really ought to know my standard J manuals better... > The very first example of Phr: 5B. Partition > http://jsoftware.com/help/phrases/partition.htm > -essentially answers my question. > Left argument to Cut (;.) -- a blind spot for me. > > On Tue, Oct 9, 2012 at 3:32 PM, Ian Clark <[email protected]> wrote: > > 1. Suppose: > > az=: 'abcdefghijklmnopqrstuvwxyz' > > i=: 3 2 5 8 5 3 NB. -(for example) > > > > How best can I partition az into parts pp where (n{pp) has length (n{i) ? > > viz. > > pp -: 'abc';'de';'fghij';'klmnopqr';'stuvw';'xyz' > > > > 2. Suppose instead of (i) I have a boolean (b) marking where to cut az > ... > > b =: 0 0 1 0 1 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 > > (c/f dyadic {enclose} in APL+) > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
