As a first step in analyzing data it is nice to have subtotals by different
parameters. I guess for example one could get total salaries, costs and
sales totaled for an entire country and subtotaled by region, sex, age of a
sales-force. Each sale can then be included in an array of 6 columns in
this case. Each subtotal would be produced with:
mt=:(/:~)@(([:~.{."1 ),.{."1 +//. }."1)
In our case,
3 mt (a: 6-column array)
would produce all sub-totals. But for all levels of sub-totals as well as
the grand total, the following would do:
m=: 4 : 0
w=. (0,{:$y)$0
u=.y
for_t. i.-x+1 do.
u=. t mt u
if. t < x do. u=. _ (<a:;t)}u end.
w=.w,u
end.
/:~w
)
on my iPad, i get:
ts'4 m ?.1000000$,: 4 5#5 100'
time: 4.39185
space: 1.97136e8
But I have not ben lucky wit a one-liner on this, I tried:
3 (}.@])`(($:<:@[)(],mt)])@.(0<[)a
|stack error
| 3 (}.@])`(($:<:@[)(],mt)])@.(0<[)a
Expecting to substitute mt into this line and get a mean one-liner.
Any hints or suggestion?
Robert Cyr
Sent from my iPad
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