Selecting Variables
Where to Specify DROP= and KEEP= Data Set Options
When match-merging,
specify these options in either the DATA statement or the MERGE statement,
depending on whether you want to reference the variables in that DATA
step:
-
To reference a variable in the original data set (in a subsetting IF statement, for example) specify the variable in the DROP= option in the DATA statement. Otherwise, you might get unexpected results and your variable would be uninitialized.
data clinic.merged (drop=id); -
To not reference certain variables and exclude them from the new data set, specify them in the DROP= option in the MERGE statement.
merge clinic.demog(in=indemog rename=(date=BirthDate)) clinic.visit(drop=weight in=invisit rename=(date=VisitDate));
When used in the DATA
statement, the DROP= option simply drops the variables from the new
data set. However, the variables are still read from the original
data set and are available for processing within the DATA step.
Last updated: January 10, 2018
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