It is neither. $1 2 +/ i. 4 2 4
Which, perhaps would explain your dilemma? Thanks, -- Raul On Thu, Sep 25, 2014 at 2:09 AM, Chris Wright <[email protected]> wrote: > thanks Robert! > > OK. boxes are atoms withb an empty shape. > > I've looked at the docs and can't see where I could read to understand why > shape of > > 1 2 +/ i. 4 > > is 2 1 and not 1 2 > > thanks for your help! > > Chris > On 25/09/2014 4:01 PM, "robert therriault" <[email protected]> wrote: > >> Hi Chris, >> >> Well there is information on the vocabulary page for Table >> http://www.jsoftware.com/help/dictionary/d420.htm >> >> also Nuvoc has good information on this verb >> http://www.jsoftware.com/jwiki/Vocabulary/slash#dyadic >> >> The actual shape of a box is empty since the box is an atom. In the case >> of 1 2 +/ i. 4 the shape is actually 2 4 i.e. 2 rows of 4 not 2 1 >> >> < 1 2 +/ i. 4 >> ┌───────┐ >> │1 2 3 4│ >> │2 3 4 5│ >> └───────┘ >> $ < 1 2 +/ i. 4 >> $ each < 1 2 +/ i. 4 >> ┌───┐ >> │2 4│ >> └───┘ >> >> If you wanted the two rows to be in their own boxes then you could do >> >> ;/ 1 2 +/ i. 4 >> ┌───────┬───────┐ >> │1 2 3 4│2 3 4 5│ >> └───────┴───────┘ >> or >> >> <"1 [ 1 2 +/ i. 4 >> ┌───────┬───────┐ >> │1 2 3 4│2 3 4 5│ >> └───────┴───────┘ >> >> $ <"1 [ 1 2 +/ i. 4 >> 2 >> >> The above shows that the shape of the two boxes is not actually 1 2 >> because each box is an atom the shape is actually just 2. >> >> You are correct that an understanding of rank and shape is key to getting >> J to work for you. If you are looking for information I have always found >> Henry Rich's J for C Programmers much more accessible than the J >> dictionary. Chapters 5 and 6 are really good at explaining rank and shape >> with regard to verbs. http://www.jsoftware.com/help/jforc/contents.htm >> >> Also, look at Nuvoc on the wiki. This is a crowd sourced resource >> organized by Ian Clark and Henry Rich which many have found useful. >> http://www.jsoftware.com/jwiki/NuVoc >> >> Enjoy the ride as you learn J. Welcome aboard. >> >> Cheers, bob >> >> >> On Sep 24, 2014, at 10:35 PM, Chris Wright <[email protected]> wrote: >> >> > Hi >> > >> > Could I work out from the docs that >> > >> > < 1 2 +/ i. 4 >> > >> > ┌───────┐ >> > >> > │1 2 3 4│ >> > >> > │2 3 4 5│ >> > >> > └───────┘ >> > >> > will give the above (2 1) shape result >> > >> > >> > and not a (1 2) result like below? >> > >> > >> > ┌───────┬───────┐ >> > >> > │1 2 3 4│2 3 4 5│ >> > >> > └───────┴───────┘ >> > >> > >> > >> > >> > With the (2,1) it's obvious that two 1-cells are returned, and with >> (1,2) >> > it's not obvious (where is the boundary b/n them), but I wonder if I >> could >> > have worked out the shape of the output from the docs alone? >> > >> > >> > with thanks >> > >> > >> > Chris >> > ---------------------------------------------------------------------- >> > 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
