Date:         Wed, 30 Jul 2008 12:22:23 -0400
Reply-To:     KNuak <asom77@HOTMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         KNuak <asom77@HOTMAIL.COM>
Subject:      current minus previous value/another approach with SAS?
Content-Type: text/plain; charset=ISO-8859-1

Hello,
Does anyone know of any other method (apart from the dif and the ifn
functions) to find
Current minus previous values?
I have dataset1 below and calculated dht= differences in ht(ie.current –
previous) and dawk=differences in awk(ie. current minus previous) all by
id below and obtained the results(output) in dataset2 below, using the ifn
and the dif functions.
*I want another approach to address the problem. Ie. an alternative
method, not using the ifn and the dif functions.
ANY ADVICE, PLEASE ON USING A DIFFERENT SAS CODE, instead of the ifn and
the dif functions.
  used the following SAS code to obtain the output in dataset2:
Data b;
Set a; /*a contains dataset1*/
By id;
Dht=ifn(first.id,(.), dif(ht));
Dawk=ifn(first.id,(.),dif(awk));
Run;

Dataset1:
  id        awk       ht
  29      4.3607     188
  29      7.1803     310
  29      9.9672     355
  31      2.0656     112
  31      3.1148     156



Dataset 2:
  id     awk     ht     dht   dawk
  29   4.3607   188     .      .
  29   7.1803    310   122   2.81967
  29   9.9672    355    45   2.78689
  31   2.0656    112    .       .
  31   3.1148    156    44  1.04918