DATA candidates;
     INPUT year candidate $  party $  outcome $ ;
DATALINES;
1976 Carter  D W
1976 Ford    R L
1980 Reagan  R W
1980 Carter  D L
1984 Reagan  R W
1984 Mondale D L
1988 Bush    R W
1988 Dukakis D L
1992 Clinton D W
1992 Bush    R L
1996 Clinton D W
1996 Dole    R L
2000 Bush    R W
2000 Gore    D L
2004 Bush    R W
2004 Kerry   D L
;
RUN;

/*
	Split into two data sets and rename variables as the two 
	new data sets are created.
*/

data winners(rename=(candidate=winner party=win_party))
     losers(rename=(candidate=loser party=lose_party));
	 set candidates;
	 if outcome = "W" then output winners;
	 else if outcome = "L" then output losers;
	 drop outcome;
run;

proc sort data=winners;
	 by year;
run;

proc sort data=losers;
     by year;
run;

data all;
     merge winners losers;
	 by year;
run;

/*
	Split into two data sets and rename variables after the two 
	new data sets are created.
*/

data winners losers;
	 set candidates;
	 if outcome = "W" then output winners;
	 else if outcome = "L" then output losers;
	 drop outcome;
run;

data winners;
     set winners;
	 rename candidate=winner
	 		party=win_party;
run;

proc sort data=winners;
	 by year;
run;

data losers;
     set losers;
	 rename candidate=loser
	 		party=lose_party;
run;

proc sort data=losers;
     by year;
run;

data all;
     merge winners losers;
	 by year;
run;