how to use by in %do

[walterwang]

I want to get one part of the data and calculate every time. for example, first time obs: 1 to 14, second time obs: 15 to 28 etc.

I  use a macro

%macro agestd_one(number);

%do i=1 %to &number %by 14;

data import;

set T0314(firstobs=&i obs=14);

run;

%end;

%mend;

I run:　

%agestd_one(14);

works well.

I run:

%agestd_one(28);

error message:

ERROR: FIRSTOBS option > OBS option - no data to read from file WORK.T0314.

what wrong at here?

[Kurt_Bremser]

obs=

has to contain the physical number of the last observation to be read, not the number of observations you want to read

firstobs=15 obs=28

will read 14 observations, not 28.

[ChrisNZ]

@Kurt_Bremser we really need an alias  lastobs=  for the  obs=  option.

[Kurt_Bremser]

You fell into a violation of the basic macro development principle: start with working code.

If you had tried

firstobs=28 obs=14

in Base SAS without the macro around it, you would have encountered the problem there, and not thought that your macro code is the culprit.

[Kurt_Bremser · Accepted solution]

A suggestion for your macro:

%macro agestd_one(number);
%do start=1 %to &number %by 14;
  %let end=%eval(&start+13);

data import;
set T0314 (firstobs=&start. obs=&end.);
run;

%end;
%mend;