Confusion about exam content guide A00-231

[zihdonv19]

Hi,

According to the exam content guide of "SAS 9.4 Base Programming – Performance Based Exam", under objective "Control which observations and variables in a SAS data set are processed and output", it has 2 sub-objectives saying "Subset variables to be output by using the DROP and KEEP statements" and "Use the DROP= and KEEP= data set options to specify columns to be processed and/or output".

Is there any difference between these 2 sub-objectives? For me, subset variables are columns, aren't they? Could someone explain this and probably give some examples regarding these two objectives? 

Many thanks!

Jane

[ballardw · Accepted solution]

Yes there is a difference. The key word in the first is "statement" compared with "data set options".

I would suggest that you use the same data set for a source of variables. Then see the difference if you attempt to use a variable that is on a Drop data set option and a Drop statement in the body of a data step.

There is a timing element involved.

Another difference is that data set options can be used with any data set used as input or output with a "date= " or "out= " in a procedure. Most procedures do not support Keep or Drop statements.

[zihdonv19]

Thanks for your answer. Indeed, I mixed "statement" up with "options".