Adding new variable with values based on conditions from another dataset

[fatemeh]

Hello all;

I have two datasets, one and two. dataset two is subset of dataset one with less observations. I want to add a numerical binary variable (z) to dataset one, that the value of z=1 for observations that are in dataset two and z=0 for those observations that are not in dataset two. Appreciate for any help.

data one;
input x1 ;
datalines;
...
;
run;

data two;
input x1;
datalines;
...
run;

[qoit · Accepted solution]

data one;
	input x1$;
	datalines;
a
b
c
d
;
run;

data two;
	input x1$;
	datalines;
a
b
run;

proc sql;
	create table three as
		select one.x1,two.x1 as x2,
			case 
				when one.x1 = two.x1 /*STRIP if needed*/
	then 1 else 0 end as z
		from one full join two
			on one.x1 = two.x1;
quit;

Does the above help, SQL is efficient as there is no previous sort required, but will need creating a third dataset.

[Reeza]

Is this based on a single value in the data set or does the whole line need to match?
You need to provide more details but otherwise, just do a MERGE and look at the IN option.

data want;
merge one (in=a) two (in=b);
by <you need to fill in>; *you have not specified the problem well enough to indicate what goes here;
if a & b then z=0;
else if b then z=1;
run;

See Example 5 in the documentation for more details.
https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=9.4_3.5&docsetId=lestmtsref&docsetTarget=n...