Date:         Mon, 27 Apr 2009 17:47:23 -0400
Reply-To:     Mike Rhoads <RHOADSM1@WESTAT.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Mike Rhoads <RHOADSM1@WESTAT.COM>
Subject:      Re: findingout consecutive days
Comments: To: "jingtailan@gmail.com" <jingtailan@GMAIL.COM>
In-Reply-To:  <1b4d9f80-43ea-4c92-ad6a-f5abd0799566@f1g2000prb.googlegroups.com>
Content-Type: text/plain; charset="us-ascii"

Jing,

The way I am thinking of this, you need to look at 3 records at the same time: the current record, the previous record, and the next record.  This is actually similar to another recent SAS-L thread.

Once you get that set up, you can set the flag according to your requirements pretty easily:

if difday <= 30 AND (prev_difday <= 30 OR next_difday < = 30)
  then flag = 'Y';
  else flag = 'N';

The DATA step below uses the LAG function to get the values from the previous record and a lookahead merge to get the values from the next record.  We also need a little code to make sure that the previous/next values are not used to set a Y unless they are for the same ID.

OPTIONS MERGENOBY = NOWARN;
data two;
merge one
  one (FIRSTOBS=2 RENAME=(id=next_id difday=next_difday));
* BY statement intentionally omitted for lookahead merge;
length flag $ 1;
keep id difday flag;
prev_id = lag(id);
prev_difday = lag(difday);
if id NE prev_id then prev_difday = 999999; /* dummy value > 30 */
if id NE next_id then next_difday = 999999; /* dummy value > 30 */
if difday <= 30 AND (prev_difday <= 30 OR next_difday < = 30)
  then flag = 'Y';
  else flag = 'N';
run;
OPTIONS MERGENOBY = ERROR;

Hope this helps.

Mike Rhoads
RhoadsM1@Westat.com


-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of jingtailan@gmail.com
Sent: Monday, April 27, 2009 4:34 PM
To: SAS-L@LISTSERV.UGA.EDU
Subject: findingout consecutive days


All;

I am working on the following question and can't get a correct code, please help. thanks a lot.

Jing tailan.



================================================================

data one;
input id difday;
datalines;
 101 0
 101 47
 101 27
 102 0
 102 17
 103 0
 103 50
 104 0
 104 12
 104 13
 105 0
 105 15
 105 10
 105 60
 106 0
 106 40
 106 15
 106 15
 107 0
 107 52
 107 51
 107 49
 ;

===================================================================

QUESTION:  how to find out the subjid who has CONSECUTIVE  difday with is <=30:

 desired result:
 101 0      n
 101 47     n
 101 27     n

 102 0      y
 102 17     y

 103 0          n
 103 50         n

 104 0          y
 104 12         y
 104 13         y

 105 0          y
 105 15         y
 105 10         y
 105 60         n

 106 0          n
 106 40         n
 106 15         y
 106 15         y

 107 0          n
 107 52         n
 107 51         n
 107 49         n