Date:         Sat, 24 Jul 2004 01:15:50 GMT
Reply-To:     Arthur Tabachneck <art297@NETSCAPE.NET>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Arthur Tabachneck <art297@NETSCAPE.NET>
Subject:      Re: Last. minus First.

Thomas,

You could try something like the following:

Art
data one;
  input id $      x       x1      x2;
  cards;
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
;
run;

data two (keep=id firstx lastx);
  retain firstx lastx;
  set one;
  by id;
  if first.id then firstx=x;
  else if last.id then do;
    lastx=x;
    output;
  end;
run;

data three (drop=firstx lastx);
  merge one two;
  by id;
  diff=lastx-firstx;
run;
------
"Thomas" <tythong@YAHOO.COM> wrote in message
news:200407240034.i6O0YQQ21115@listserv.cc.uga.edu...
> 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