Merging Data Sets Faster
When merging two SAS data sets, many of us use one of these two methods to keep only the observations where both input data sets contribute:data test1;
merge step1(in=a)
step2(in=b);
by district studentid;
if a=1 and b=1;
run;
or
data test1;
merge step1(in=a)
step2(in=b);
by district studentid;
if a and b;
run;
This method executes faster (and saves a few keystrokes):
data test1;
merge step1(in=a)
step2(in=b);
by district studentid;
if a*b;
run;
This shortened version of the IF statement works since if either the variable a or b is false, the expression resolves to zero (false).
posted by Linda J. Adams @ 12:24 PM
4 Comments:
This is great. Thanks, Linda.
just tested with million level pseduo data set, no practical difference.
Hey Anonymous @ 3:38 PM, you can't just walk past a bowl of cornflakes, can you?
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