> From: Zsbán Ambrus > > You have to box the data again before you reassemble it. Some other > messages show tricky ways to do this automatically with the under conj > (or even level, yuck), but it's probably easier to do it by hand. ... > > and then you can apply this verb to the whole boxed list: > > < b_jonas> ):: ([: < mm # >)"0 t1 > < jeval> b_jonas: +--------+--------+--------+--------+ > < jeval> b_jonas: |20090904|20090903|20090902|20090901| > < jeval> b_jonas: +--------+--------+--------+--------+
I think this is a useful approach from a didactic point of view - it is essentially a model of the approach using the under conjunction. However from a practical point of view it doesn't really make use of J's strengths (because it works with small bits of data at a time). Bill's approach (<"1 mm #"1 > t1) does the same thing but on bigger bits of data at a time resulting in faster, leaner performance. Comparing this approach to that using the under conjunction highlights the performance improvements of the code optimizations to &.> : 30 ts 'mm&# &.>tst' NB. Using under 0.0312943447319 7334976 30 ts '<"1 mm#"1>tst' NB. Working on big chunks 0.0391365798689 9432512 30 ts '([: < mm # >)"0 tst' NB. Working on little chunks 0.188038321345 15078848 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
