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
