Thanks Ambrus and Bill. I'll add these to my private idioms list.
Ian
On Mon, Feb 15, 2010 at 1:19 PM, Zsbán Ambrus <amb...@math.bme.hu> wrote:
> On Sun, Feb 14, 2010 at 5:49 AM, Ian Clark <earthspo...@googlemail.com> wrote:
>> 1. If I have a M-by-N table with entries like this
>> ...
>> {. curlylfdot
>>
>> {:: curlylfcoco {: curlylfco
>> } curlyrt
>> ...
>>
>> how do I neatly slice off the first 3 columns (say) into a boxed list
>> of tally M to serve as a lookup index?
>
> In this case, you could cheat by
>
> st=: 0 :0
> {. curlylfdot
> {: curlylfco
> {:: curlylfcoco
> } curlyrt
> )
> ]li=: <;._2 st
> +--------------+-------------+---------------+-----------+
> |{. curlylfdot|{: curlylfco|{:: curlylfcoco|} curlyrt|
> +--------------+-------------+---------------+-----------+
> ]wo=: ;:&> li
> +---+-----------+
> |{. |curlylfdot |
> +---+-----------+
> |{: |curlylfco |
> +---+-----------+
> |{::|curlylfcoco|
> +---+-----------+
> |} |curlyrt |
> +---+-----------+
>
> If you really want to use a fixed width first column, then try
>
> ]wo=: 3 ({.;}.)&> li
> +---+------------+
> |{. | curlylfdot |
> +---+------------+
> |{: | curlylfco |
> +---+------------+
> |{::| curlylfcoco|
> +---+------------+
> |} | curlyrt |
> +---+------------+
>
> Ambrus
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
