Date:         Fri, 26 Oct 2007 06:05:16 -0700
Reply-To:     Peter <crawfordsoftware@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Peter <crawfordsoftware@GMAIL.COM>
Organization: http://groups.google.com
Subject:      Re: assign the same ids for the same by variables
Comments: To: sas-l@uga.edu
In-Reply-To:  <6.2.3.4.2.20071025124452.056a08e0@postoffice7.mail.cornell.edu>
Content-Type: text/plain; charset="us-ascii"

On 25 Oct, 17:45, f...@CORNELL.EDU (Florio Arguillas) wrote:
> Hi Wang,
>
> Try this one.
>
> Best regards,
>
> Florio
>
> data have;
> infile cards;
> input identity_num $;
> cards;
> A
> A
> A
> B
> B
> C
> C
> C
> C
> D
> D
> ;
>
> data need;
>          set have;
>          by identity_num;
>          if first.identity_num then study_id+1;
> run;
>
> At 11:56 AM 10/25/2007, Ai Hua Wang wrote:
>
>
>
> >Hi List:
>
> >I have searched the listserve archive. But for some reason I could
> >not find anything. This is probably because my key words are not
> >appropriate. Could anybody in the list help me on the following
> >task? I need to assign the same ids for the the same by variables. I
> >list the sample data in the following:
>
> >identity_num
> >A
> >A
> >A
> >B
> >B
> >C
> >C
> >C
> >C
> >D
> >D
>
> >I want the output looks like the following:
>
> >identity_num      study_id
> >A                            1
> >A                            1
> >A                            1
> >B                            2
> >B                            2
> >C                            3
> >C                            3
> >C                            3
> >C                            3
> >D                            4
> >D                            4
>
> >I write the following SAS codes to accomplish the task. But I got
> >errors. I guess the errors are caused by the do loop. I need your
> >help on fixing the do loop. I am sorry this is probably a very simple question.
>
> >Thanks,
> >Wang
>
> >data out1;
> >by identity_num;
> >set have;
> >n=1;
> >length study_id 3;
> >do j=first.identity_num to last.identity_num;
> >study_id = n;
> >n+1;
> >end;
> >run;
>
> >__________________________________________________
> >Do You Yahoo!?
> >Tired of spam?  Yahoo! Mail has the best spam protection around
> >http://mail.yahoo.com- Hide quoted text -
>
> - Show quoted text -

lets get brief.
use the special features provided with by-group processing in a data
step - - first.{by-variable}
That will be true(=1) when the obs read is first for the study group,
otherwise false(=0).

data wanted;
  set have;
   by identity_num ;
  study_id + first.identity_num ;
run;

Reduced to the size of the problem, by
Peter.C