output previous row

[eduard1231]

This is the sample code 

data a_k resid;
set akkk;
if mad_command ne 0 then do; output resid and ....; end;
run;

So, what I am trying to do is that if mad_command ne 0, then ouput the whole row to resid table AND ALSO OUTPUT the previous row to resid table as well. 

Thanks

[novinosrin]

Hello @eduard1231 

Are you asking for this kinda logic?

data have;
input var ;
cards;
0
0
4
1
2
;


data want;
set have;
if var ne 0 then do;
output;
n=_n_-1;
set have point=n;
output;
end;
run;

[mkeintz · Accepted solution]

This is where using the POINT= option of the SET statement helps:

data a_k resid;
  set akkk;
  output a_k;

  if mad_command ne 0 then do; 
    output resid;
    p=_n_-1;
    set akkk point=p;
    output resid;
  end;
run;

This program outputs every akkk record to dataset a_k.  If outputs the selected record, and its predecessor to resid.  Note the original preceding record now follows the precipitating record.  If instead you want to preserve the original order, you can:

data a_k resid;
  set akkk;
  output a_k;

  if mad_command ne 0 then do p=_n_-1 to _n_;
    set akkk point=p;
    output resid;
  end;
run;