Date:         Thu, 28 Jun 2007 07:09:48 -0700
Reply-To:     frank_diiorio@YAHOO.COM
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Frank DiIorio <frank_diiorio@YAHOO.COM>
Organization: http://groups.google.com
Subject:      Re: Count the proportion of days with exposure in specified time
              period
Comments: To: sas-l@uga.edu
In-Reply-To:  <1183036458.595910.97360@q75g2000hsh.googlegroups.com>
Content-Type: text/plain; charset="us-ascii"

On Jun 28, 9:14 am, SK <skauch...@gmail.com> wrote:
> Hi there, this is a newbie-type question.
>
> I have a longitudinal dataset of daily feeding records of infants from
> birth to 270 days (9 months). Infant feeding (category) for the each
> day is recorded at either exclusive breast =1), mixed feeding (=2),
> and exclusive formula (=3). I wish to count the proportion of days a
> child receives either 1, 2 or 3.
>
> Data structure and intended variable after manipulation (propfeed):
>
> id         Feed
> 1            1
> 1            1
> 1            2
> 1            3
> 2            1
> 2            1
> 2            1
> 2            1
> 3            3
> 3            3
> 3            3
> etc
>
> Desired table:
> id          propfeed1            propfeed2      propfeed3
> 1              0.5                      0.25                0.25
> 2               1.0                       0                    0
> 3               0                          0                   1.0
> etc.
>
> Could someone help guide me through this problem?
> thank you,
>
> SK

Here's an SQL-based solution:

proc sql noprint;
     create table summ as
     select sum(feed=1)/count(*) as propFeed1 format=4.2,
            sum(feed=2)/count(*) as propFeed2 format=4.2,
            sum(feed=3)/count(*) as propFeed3 format=4.2
     from propFeed
     group by id
     ;
quit;