In the context of that "three star programmer" thing, it might be worth noting that in C, x[0] is the same as *x.
-- Raul On Wed, Jun 7, 2017 at 5:29 AM, 'Jon Hough' via Programming <[email protected]> wrote: > Thanks, I was worried I was doing something out of the ordinary, or going > down a wrong path. It's odd because I don't see multiple " very often (but > then I probably don't read other people's code enough). > > When you wrote: >> I use u"r1"r2 (two >> ranks) pretty often, three ranks very rarely, and >> have never had a use for four ranks. > > It reminded me of C, and the Three Star Programmer > http://wiki.c2.com/?ThreeStarProgrammer > I half wonder if there are any 4-" J programmers? > > > -------------------------------------------- > On Wed, 6/7/17, Henry Rich <[email protected]> wrote: > > Subject: Re: [Jprogramming] Verb Rank Misunderstandings with " > To: [email protected] > Date: Wednesday, June 7, 2017, 6:03 PM > > Yes, that's the normal way to > do this. You can also use > > data -"1/ other > > which is the same as > > data -"1"1 _ other > > giving result shape 4 2 4 (i. > e. a transpose of what you got). > > > I use u"r1"r2 (two > ranks) pretty often, three ranks very rarely, and > have never had a use for four ranks. > > Henry Rich > > On 6/7/2017 4:12 AM, 'Jon Hough' via > Programming wrote: > > Assume I have a > dataset of shape 4 4 > > data=: 4 4 $ i. > 16 > > > > and some other > data of shape 2 4 (i.e. same number of columns, different > number of rows) > > > > > other=: 2 4 $ 100 200 130 250 2 4 6 8 > > > > I want to subtract > each row of other from data, so that the result has shape > 2 4 4. i.e. I know the result of each row of > > other subtracted from the whole of > data. > > The way I do this is: > > > > data -"1 > 1"_ 1 other > > > > > For me, at least, chaining " is a new concept. I > didn't know it was possible until relatively recently. I > find it slightly ugly because, for me, it is very difficult > to figure out how the ranks of the verb and the nouns all > interact. But is this a J-esque way to > > > solve the above problem? Are there other ways to solve > it? > > > > Extra: > > Because the above example is slightly > contrived, I will just give a more concrete example. Suppose > I have a dataset X, of shape A B, > > and I > have a collection, Y, of "average values" of other > datasets, where the collection has shape C B, each row of Y > being an average of > > some dataset. > > I want to know the values of the first > dataset minus each average. So > > X > -"1 1"_ 1 Y gives this result, and it has shape C > A B. > > > > Thanks, > > Jon > > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > --- > This email has been checked for viruses by > AVG. > http://www.avg.com > > ---------------------------------------------------------------------- > 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
