Date: Fri, 18 Apr 2003 18:37:04 +0000
Reply-To: sashole@bellsouth.net
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Paul Dorfman <paul_dorfman@HOTMAIL.COM>
Subject: Re: recoding variables
Content-Type: text/plain; format=flowed
>From: L F <tyroc7@HOTMAIL.COM>
>
>I have a series of 16 variables let's call them relate1-relate16. I have
>another variable called married. If any of the relate1-relate16 variables
>has a value of 2 or a value of 11 I would like the married variable to take
>on a value of 1. Otherwise the value of married should be 0.
>
>Can anyone recommend a succinct way of doing this without having to 16
>if/else statements?
LF,
In principle, the process can be made completely IF-less (R is short for
Relate):
array r (16) ;
married = index (peekc(addr(r1), dim(r)*8), put(02,rb8.))
| index (peekc(addr(r1), dim(r)*8), put(11,rb8.)) ;
If this is to be done in each of great many observations, it is better to
compute much of the stuff once beforehand, for example:
220 data r ;
221 array r (7) ;
222 input r(*) ;
223 list ;
224 cards ;
RULE: ----+----1----+
225 1 2 3 4 5 6 11
226 1 2 3 4 5 6 .
227 1 . 3 4 5 6 11
228 1 . 3 4 5 6 .
229 2 . 3 4 5 6 .
230 1 . 3 4 5 11 .
231 ;
232 run ;
NOTE: The data set WORK.R has 6 observations and 7 variables.
233
234 data _null_ ;
235 array r (7) ;
236 rb02 = put (02, rb8.) ;
237 rb11 = put (11, rb8.) ;
238 a1 = addr (r1) ;
239 dimr = dim (r) ;
240 do until ( eof ) ;
241 set r end = eof ;
242 memstr = peekc (addr(r1), dimr * 8) ;
243 married = index (memstr, rb02) | index (memstr, rb11) ;
244 put (r(*)) (z2. +1) +1 married= ;
245 end ;
246 run ;
01 02 03 04 05 06 11 married=1
01 02 03 04 05 06 . married=1
01 . 03 04 05 06 11 married=1
01 . 03 04 05 06 . married=0
02 . 03 04 05 06 . married=1
01 . 03 04 05 11 . married=1
Jusge for yourself if the method is succinct enough or not. If not, you can
process the array one element at a time, as others have indicated. I would
also dare offer my own, more efficient, variant of this approach (input
being the same):
387 run ;
388
389 data _null_ ;
390 array r (8) (8 * 2) ; *could code 11 instead ;
391 set r ;
392 do inx = 1 by 1 until ( r(inx) in (2, 11) ) ;
393 end ;
394 married = inx LE hbound(r) - 1 ;
395 put (r(*)) (z2. +1) +1 married= ;
396 run ;
01 02 03 04 05 06 11 02 married=1
01 02 03 04 05 06 . 02 married=1
01 . 03 04 05 06 11 02 married=1
01 . 03 04 05 06 . 02 married=0
02 . 03 04 05 06 . 02 married=1
01 . 03 04 05 11 . 02 married=1
I will let you (and others if they are interested) to ponder why the
bodyless loop above (relying on the setinel located in the extra array item
for stoppage) makes for higher computer efficiency.
Kind regards,
-------------------
Paul M. Dorfman
Jackonsville, FL
-------------------
_________________________________________________________________
The new MSN 8: smart spam protection and 2 months FREE*
http://join.msn.com/?page=features/junkmail
