Short answer: there is no efficient way (and I find this to be a huge problem).
The most recent thread on this topic is here: http://jsoftware.com/pipermail/programming/2015-February/041005.html Marshall On Tue, Jun 23, 2015 at 01:53:36AM +0000, Marshall Bockrath-Vandegrift wrote: > Hi all, > > I'm still in the process of learning J, and trying to adapt ideas from > other languages. In many (other?) functional programming languages it is > possible to reduce over a collection starting with a provided initial value > which does not belong to the reduced collection. To attempt to put this in > J terms, such an operation would allow the initial value and result of each > reduction step to have a different shape than that of the the items of the > value being reduced. As far as I can tell, the standard `/` adverb provides > no such facility. Is there a J idiom for this? > > Thanks, > > -Marshall > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
