topic How Drop statement will work here? in ODS and Base Reporting

How Drop statement will work here?

sravanpathu — Thu, 17 Oct 2013 16:35:31 GMT

Hi SAS Wrold,

I had Below dataset called Test.

A B C ------------------ Variables

a 1 2

b 2 4

c 3 6

d 4 0

I have written program

Data Test1;

Set Test;

If A='d' Then Do;

If B <=0 Then Do;

Drop B;

end;

If C <=0 Then Do;

Drop C;

end;

run;

When am executing above program in output dataset Test1 both Variable B and C got droped. Can anybody help me how it is working.

Regards,

SAS_Sravan

Re: How Drop statement will work here?

ballardw — Thu, 17 Oct 2013 17:19:26 GMT

Drop statements are not conditional, if in the code they will drop the variable. Since the purpose of Drop is to remove the Variable from the dataset that makes sense. You may actually want to set B and C to missing values.

Maybe you should provide an example of your input data and the desired outcome and possibly describe what you are going to do with the resulting data.

Re: How Drop statement will work here?

esjackso — Thu, 17 Oct 2013 18:03:11 GMT

Do you want to remove the row instead? you can conditionally delete observations using if b<=0 then delete.

Also you dont need do loop for one action.

Re: How Drop statement will work here?

mike629 — Mon, 18 Nov 2013 18:27:14 GMT

IF won't affect the execution of DROP here.

Re: How Drop statement will work here?

Patrick — Mon, 18 Nov 2013 19:26:49 GMT

During compilation phase of a data step SAS scans the code to determine and create all variables - also for the output data set(s). Think of it as the "header" of the data set (descriptor information).

SAS(R) 9.2 Language Reference: Concepts, Second Edition

SAS data sets are orthogonal so you can't have a variable in one row and then not in another row. That's why it makes sense that DROP can't be used conditionally during the execution phase of the data step but is used during compilation phase.