On Thu, Sep 8, 2011 at 12:21 PM, David Vaughan <[email protected]> wrote: > Could you explain how the ":&.> part works please? I don't really understand > &. from the vocabulary section. ... >> ;":&.>1+i.20 >> 1234567891011121314151617181920
Given a verb V, the expression V&.> is equivalent to the expression <@:V@> Or, more generally, given verbs V and W the expression V&.> is equivalent to the expression W inv@:V@W In other words, > (or W) is used as a preprocessor, and its inverse is used as a post processor. Note also that the rank of W determines the rank of later stages of the pipeline. Thus, since > is rank 0, each number is individually formatted and boxed in ":&.> And, in this case, I am relying on > doing nothing to numbers (other than setting the rank of the verb). So an alternate expression which would do the same thing is: ;<@:":"0>:i.20 or ;<@:":"0(1+i.20) FYI, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
