Beginner questions are welcomed. Here's one way to include empty boxes for
keys without any values:
] DATA=: 0 0 1 1 1 1 2 2 2 2 2 4 4 4 5 5,: 5 0 7 8 9 2 2 5 5 5 3 8 0 0 5
6
0 0 1 1 1 1 2 2 2 2 2 4 4 4 5 5
5 0 7 8 9 2 2 5 5 5 3 8 0 0 5 6
~.0{DATA NB. Existing keys
0 1 2 4 5
]AllKeys=. i.7 NB. Assume these are all possible keys
0 1 2 3 4 5 6
NB. Extra ....... keys, dummy ....... values corresponding to extras,
}. &.> (AllKeys,0{DATA) < /. AllKeys,1{DATA
+---+-------+---------++-----+---++
|5 0|7 8 9 2|2 5 5 5 3||8 0 0|5 6||
+---+-------+---------++-----+---++
NB. " }.&.> " drops dummies from result.
On Tue, Jan 10, 2012 at 9:40 AM, Ben Gorte - LR <b.g.h.go...@tudelft.nl>wrote:
> Dear Forum,
>
> Perhaps it is a beginners question, but somehow I cannot come up with a
> decent answer.
>
> I have a matrix like of position-value pairs like:
>
> 0 0 1 1 1 1 2 2 2 2 2 4 4 4 5 5
> 5 0 7 8 9 2 2 5 5 5 3 8 0 0 5 6
>
> (it could also be transposed), and I would like to have a list of boxes:
>
> +---+-------+---------++-----+---+
> |5 0|7 8 9 2|2 5 5 5 3||8 0 0|5 6|
> +---+-------+---------++-----+---+
>
> So the values are placed in boxes according to the positions.
>
> My matrix above is sorted (from left to right), but probably this is not
> essential for most solutions. Furthermore, the order of the elements within
> the boxes of the result is not important for the remainder of my algorithm.
>
> I have a solution that loops through the matrix from left to right, but it
> is way too slow (and it does not look like J). Isn't there a better way?
>
> Thanks,
> Ben
>
>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
--
Devon McCormick, CFA
^me^ at acm.
org is my
preferred e-mail
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
