|Date: ||Thu, 17 Jul 2003 15:27:22 -0400|
|Reply-To: ||"Fehd, Ronald J. (PHPPO)" <rjf2@CDC.GOV>|
|Sender: ||"SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>|
|From: ||"Fehd, Ronald J. (PHPPO)" <rjf2@CDC.GOV>|
|Subject: ||Re: processing question|
> From: Shannon [mailto:shannon_ritter@ALUMNI.ALBANY.EDU]
> Suppose you want to perform a similar operation on a group of
> variables in the same data set. I usually do this with a
> macro do loop. In the current situation I run a proc contents
> and then subset based on a substring in the output NAME
> variable. This substring then becomes necessary in and after
> the macro do loop. The result of the do loop is a data set
> that is 1-1 merged with the contents
> output(subsetted) data set. The question is should I create
> the substring variable before the do loop (which would
> involve an extra data step) or after the do loop (in a data
> step I need anyway)? In the latter case I actually end up
> creating the substring 3 times, once for the first subsetting
> (with a where option on the out= data set), once in the macro
> do loop (using %substr) and the third time for keeps after
> the do loop (by assignment). In the former case I need an
> extra data step.
this sounds similar to an algorithm I use.
I recommend creating your necessary variable
-- which name is the prefix of the group --
as early as possible
which I think, according to your description,
'involves an extra data step'.
In this preprocessing data step
you can completely declare your data structure
which is always a Good Thing.
Ron Fehd the macro maven CDC Atlanta GA USA RJF2@cdc.gov
Your task is simple: remove the difference
between how things should be
and how they really are.
-- Ashleigh Brilliant pot-shot #4247
... as early as possible.