Randy A MacDonald wrote: > That (4&$.)^:_1 does not return the original table is > not important to me.
That's not an inverse. > That it returns a useful result is. Useful for what? What's wrong with something like [EMAIL PROTECTED] [:(] #: i.@:>:)>./ ? For example: It seems to me it would be useful to upgrade the sparse version of e. such that e.&$.~ [:(] #: i.@:>:)>./ is equivalent to (but more space efficient than) my previous expression. It seems to me that upgrading #: to support sparse arguments (or, at least, to avoid crashes in cases such as (]#:i.)$.2 2) would be useful. Anyways... there's lots of different kinds of "useful". Thanks, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
