Fractional axes specs are an abomination. Don't bother trying to model it.
,: and ,:"r are far superior. On Thu, Sep 11, 2014 at 7:00 AM, Dan Bron <[email protected]> wrote: > Ben Gorte wrote: > > I use an adverb called ins that behaves like } , except that it inserts > :) > > In the argument to the adverb, does 1 ins refer to the item at index 1 in > the argument, or the empty space between item 1 and item 2, or the empty > space between item 0 and item 1, or what? > > If I recall correctly, in APL, you can use fractional indices to specify > inserting along a new axis, so 'hello' ,[0.5] '-' would be equivalent to > J's 'hello' ,: '-' and 'hello' ,[1.5] '-' would be 'hello' ,. '-' > (assuming []IO<-1 in the APL). > > Maybe it's worth including an ins-like adverb in the stdlib which follows > this convention (fractional indices refer to the lacunae between items)? > > -Dan > > PS: Looks like Dyalog, at least, supports fraction axes; see p. 236 of > their user guide (Chapter 4, "Catenate/Laminate", Section 2.15.2 > "Lamination with Fractional Axis Specification"): > > > http://docs.dyalog.com/13.1/Dyalog%20APL%20Programmer's%20Guide%20&%20Language%20Reference.pdf > > > Lamination with Fractional Axis Specification > --------------------------------------------- > > The arrays X and Y are joined along a new axis created before > the {ceil}Kth axis. The new axis has a length of 2. K must exceed > []IO (the index origin) minus 1, and K must be less than []IO plus > the greater of the ranks of X and Y. A scalar or unit vector argument > is extended to the shape of the other argument. Otherwise X and Y > must have the same shape. The rank of R is one plus the greater of > the ranks of X and Y. > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
