topic Re: adapting moving average code for additional dimension in SAS Programming

adapting moving average code for additional dimension

csetzkorn — Tue, 28 Mar 2017 19:57:54 GMT

Looking at the code taken from here to calculate the moving average for one dimension/category patient:

data ds1;
  do patient='A','B','C';
    do month=1 to 7;
      num=int(ranuni(0)*10);
      output;
      end;
    end;
run;

proc sort;
  by patient;
run;

%let n = 4;

data ds2;
  set ds1;
  by patient;
  retain num_sum 0;
  if first.patient then do;
    count=0;
    num_sum=0;
  end;
  count+1;
  last&n=lag&n(num);
  if count gt &n then num_sum=sum(num_sum,num,-last&n);
  else num_sum=sum(num_sum,num);
  if count ge &n then mov_aver=num_sum/&n;
  else mov_aver=.;
run;

title 'Moving average within BY-Group';
proc print;
run;

I am wondering if this could be adapted for an additional dimenension/category Cat1. A starting point would be:

data ds1;
  do patient='A','B','C';
  	do Cat1='C1','C2';
	    do month=1 to 7;
	      num=int(ranuni(0)*10);
	      output;
	    end;
	end;
  end;
run;

proc sort;
  by patient Cat1;
run;

Any help would be very much appreciated. Thanks a lot.

Re: adapting moving average code for additional dimension

Reeza — Tue, 28 Mar 2017 20:08:56 GMT

1. Change BY statement in SORT (done & shown) and Data Step (DS2)

2. Any time you see a reference to first.patient change it to first.cat1

I think that's all...but untested.

@csetzkorn wrote:

Looking at the code taken from here to calculate the moving average for one dimension/category patient:

data ds1;
  do patient='A','B','C';
    do month=1 to 7;
      num=int(ranuni(0)*10);
      output;
      end;
    end;
run;

proc sort;
  by patient;
run;

%let n = 4;

data ds2;
  set ds1;
  by patient;
  retain num_sum 0;
  if first.patient then do;
    count=0;
    num_sum=0;
  end;
  count+1;
  last&n=lag&n(num);
  if count gt &n then num_sum=sum(num_sum,num,-last&n);
  else num_sum=sum(num_sum,num);
  if count ge &n then mov_aver=num_sum/&n;
  else mov_aver=.;
run;

title 'Moving average within BY-Group';
proc print;
run;

I am wondering if this could be adapted for an additional dimenension/category Cat1. A starting point would be:

data ds1;
  do patient='A','B','C';
  	do Cat1='C1','C2';
	    do month=1 to 7;
	      num=int(ranuni(0)*10);
	      output;
	    end;
	end;
  end;
run;

proc sort;
  by patient Cat1;
run;

Any help would be very much appreciated. Thanks a lot.

Re: adapting moving average code for additional dimension

csetzkorn — Tue, 28 Mar 2017 20:20:29 GMT

Thanks. Are you sure the sort has only to be done for one dimension? Please note that the data generation code is just an example and the data can be in any order. Ultimately the MA is to be applied at the time dimension month.

Re: adapting moving average code for additional dimension

Reeza — Tue, 28 Mar 2017 20:34:30 GMT

What do you mean the sort is by one dimension? Your proc sort showed two variables in the BY statement. That's what you need. In both BY statements, the data step and sort.

And the fastest way is to answer this is to test it out 🙂