BookmarkSubscribeRSS Feed
Melk
Lapis Lazuli | Level 10

I have a data set structured as follows:

 

ID                repeat             firstID

1                     0

2                     0

3                     1                   2

4                     0          

5                     0

6                     1                  4,5

 

 

So I need to keep only the new IDs for patients who were repeats. In this example, I would need to remove 2, 4, 5. Some have multiple previous IDs, so there is a comma separating them. What is the most efficient way to do this?

 

 

3 REPLIES 3
ChrisBrooks
Ammonite | Level 13

Making some assumptions about the format of the data and the variables you want to keep in the output this should give you what you're asking for

 

data have;
	length id $1 repeat 8. firstid $3;
	infile datalines dlm='09'x missover truncover;
	input id repeat firstid;
	datalines;
1	0
2	0
3	1	2
4	0
5	0
6	1	4,5
;
run;

proc sql;
	create table repeats
	as select firstid
	from have
	where firstid ne "";
quit;

data repeatslong(keep=id);
	set repeats;
	if count(firstid,",") > 0 then do;
		do i = 1 to (count(firstid,",")+1);
			id=scan(firstid,i,",");
			output;
		end;
	end;
	else do;
		id=firstid;
		output;
	end;
run;

proc sql;
	create table want
	as select id, repeat
	from have
	where id not in
		(select id
		 from repeatslong)
	;
quit;

 

Patrick
Opal | Level 21

@Melk

I tend to use SAS hash tables to create black-lists or white-lists. Below an example.

data have;
	length id $1 repeat 8. firstid $3;
	infile datalines dlm='09'x truncover;
	input id repeat firstid;
	datalines;
1	0
2	0
3	1	2
4	0
5	0
6	1	4,5
;
run;

data want(drop=_:);

  if _n_=1 then
    do;
      dcl hash h1();
      h1.defineKey('id');
      h1.defineDone();

      do until(last);
        set have(keep=firstid) end=last;
        if not missing(firstid) then
          do _i=1 by 1;
            id=scan(firstid,_i,',');
            if missing(id) then leave;
            h1.ref();
          end;
      end;
    end;

    set have;
    if h1.check() then output;

run;

 

s_lassen
Meteorite | Level 14

@Melk:

You can also do it with a relatively simple datastep solution:

data have;
  length id $1 repeat 8. firstid $3;
  infile cards truncover;
  input id repeat firstid;
cards;
1 0
2 0
3 1 2
4 0
5 0
6 1 4,5
;
run;

data drop;
  set have;
  where firstid;
/* parse firstid */ do _N_=1 to countw(firstid,',');
id=scan(firstid,_N_,','); output; end; keep id; run; proc sort data=drop; by id; run; data want; merge have drop(in=drop); by id; if not drop; run;

sas-innovate-2024.png

Join us for SAS Innovate April 16-19 at the Aria in Las Vegas. Bring the team and save big with our group pricing for a limited time only.

Pre-conference courses and tutorials are filling up fast and are always a sellout. Register today to reserve your seat.

 

Register now!

How to Concatenate Values

Learn how use the CAT functions in SAS to join values from multiple variables into a single value.

Find more tutorials on the SAS Users YouTube channel.

Click image to register for webinarClick image to register for webinar

Classroom Training Available!

Select SAS Training centers are offering in-person courses. View upcoming courses for:

View all other training opportunities.

Discussion stats
  • 3 replies
  • 791 views
  • 3 likes
  • 4 in conversation