Assigning values by group

[JJ_83]

Hello, 

I want to assign the same start and end date by matching variable. Any advice?

data have;
	input id $ matching $ start :mmddyy10. end :mmddyy10.;
	format	start mmddyy10.
			end mmddyy10.;
	datalines;
		B0000362004	A 01/01/2001 11/11/2011
		B0005852005 A . . 
		B0009422005 B 02/02/2002 12/12/2012
		B1370912010 B . .
	;
run;

data want;
	input id $ matching $ start :mmddyy10. end :mmddyy10.;
	format	start mmddyy10.
			end mmddyy10.;
	datalines;
		B0000362004	A 01/01/2001 11/11/2011
		B0005852005 A 01/01/2001 11/11/2011 
		B0009422005 B 02/02/2002 12/12/2012
		B1370912010 B 02/02/2002 12/12/2012
	;
run;

[ballardw]

This seems to work for your example data.

data want;
   set have;
   retain lstart lend;
   lstart = coalesce(start,lstart);
   lend   = coalesce(end,lend);
   start = coalesce(start,lstart);
   end   = coalesce(end,lend);
   drop lstart lend;
run;

Retain will keep values across records. The Coalesce (and Coalescec for character values) returns the first non-missing value in the list and is basically used to avoid a bunch of similar "if missing(var) then var=varb;" type statements.

Note If you do NOT actually want to carry the dates forward with the ID changes then you need to state so and indicate what should be done. The above code ignores the ID.

[novinosrin · Accepted solution]

data have;
	input id $ matching $ start :mmddyy10. end :mmddyy10.;
	format	start mmddyy10.
			end mmddyy10.;
	datalines;
		B0000362004	A 01/01/2001 11/11/2011
		B0005852005 A . . 
		B0009422005 B 02/02/2002 12/12/2012
		B1370912010 B . .
	;
run;

data want;
 update have(obs=0) have;
 by  matching;
 output;
run;