Date:         Mon, 1 Sep 2008 15:08:42 -0400
Reply-To:     msz03@albany.edu
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Mike Zdeb <msz03@ALBANY.EDU>
Subject:      Re: Keeping first and every 30th record
Content-Type: text/plain;charset=iso-8859-1

hi ... if you are sure that you have data for each age and they are in age order, the MOD function
solution posted by Alex is fine

but, since you are looking for observations based on the value of the variable AGE, why not use
that variable value rather than position in the data set to select observations

data ds2;
set ds1;
where age eq 1 or mod(age,30) eq 0;
run;

--
Mike Zdeb
U@Albany School of Public Health
One University Place
Rensselaer, New York 12144-3456
P/518-402-6479 F/630-604-1475

> Hello everyone, I have a dataset, ds1 made up of age(days) and height, ht
> (cm). The age  begins from day 1 through to day 300. I want to have an
> output,ds2 starting at day 1, then day 30, 60,90….. day 300. ie. I want to
> pull out from ds1, days 1,30,60,….300,with their heights (ht’s). ie.
> day1,day 30 and every 30th record up to the end of the dataset.
>
>   Ds1
> age     ht
> 1        13
> 2        17
> 3        22
> 4        26
> 5        22
> ...
> 30      44
> 31      46
> ..
> 270    145
> 271    144
> ..
> 300    298
>
>
> ds2
> age  ht
> 1    13
> 30   44
> 60   55
> 90   89
> 120  123
> 150  150
> 180  166
> 210  195
> 240  242
> 270  145
> 300  298
>
> • ie. in Ds2(output), I want to keep day 1 and every 30th record up
> to the end (day300), along with their corresponding ht.
> • Could someone help me with the SAS code, please to arrive at ds2?
>
>