Date:         Fri, 23 Jul 2004 20:34:25 -0400
Reply-To:     Thomas <tythong@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Thomas <tythong@YAHOO.COM>
Subject:      Last. minus First.

Hi all,

I have a dataset as belows, how do I compute the (Last.x - First.x), last
value of x minus first value of x, for each id? The input and desired
output are attached as belows.

Thanks a lot!
Thomas

*input;
id      x       x1      x2
a      10       0.5     0.9
a      11       0.55    0.8
a      12       0.5     0.6
a      13       0.45    0.55
b      1        0.1     0.15
b      2        0.2     0.25
b      3        0.15    0.2

*expected output;
id     x        x1      x2      diff
a      10       0.5     0.9     3
a      11       0.55    0.8     3
a      12       0.5     0.6     3
a      13       0.45    0.55    3
b      1        0.1     0.15    2
b      2        0.2     0.25    2
b      3        0.15    0.2     2