topic Re: Add consecutive numbers in between of the dataset in SAS Programming

Add consecutive numbers in between of the dataset

chithra — Thu, 28 Mar 2019 08:45:52 GMT

Dear All,

I am having a data set like below :

id	scn	year	value
89	1	168	100000
89	1	169	0
89	1	169	111111
89	1	171	0
89	1	171	0
89	1	172	100003
89	1	179	100004
89	1	180	0
89	2	168	100006
89	2	169	0
89	2	172	100008

The columns id,scn and year is sorted in ascending order, i mean all are group by.

year column should be consecutive numbers, but here some year are missing, I need to add consecutive numbers in between with value as 0.

i need to do this in data step becuase it is very huge data, multiple steps will cause performance issue.

The output should lokks like :

id	scn	year	value
89	1	168	100000
89	1	169	0
89	1	169	111111
89	1	170	0
89	1	171	0
89	1	171	0
89	1	172	100003
89	1	173	0
89	1	174	0
89	1	175	0
89	1	176	0
89	1	177	0
89	1	178	0
89	1	179	100004
89	1	180	0
89	2	168	100006
89	2	169	0
89	2	170	0
89	2	171	0
89	2	172	100008

Thanks in Advance,

Chithra

Re: Add consecutive numbers in between of the dataset

Kurt_Bremser — Thu, 28 Mar 2019 09:33:19 GMT

Create a "look-ahead":

data have;
infile datalines dlm='09'x dsd;
input id $ scn year value;
datalines;
89	1	168	100000
89	1	169	0
89	1	169	111111
89	1	171	0
89	1	171	0
89	1	172	100003
89	1	179	100004
89	1	180	0
89	2	168	100006
89	2	169	0
89	2	172	100008
;
run;

data want;
merge
  have
  have (
    firstobs=2
    keep=id scn year
    rename=(
      id=n_id
      scn=n_scn
      year=n_year
    )
  )
;
output;
if n_id = id and n_scn = scn
then do year = year + 1 to n_year - 1;
  value = 0;
  output;
end;
drop n_:;
run;

proc print data=want noobs;
run;

Result:

id    scn    year     value

89     1      168    100000
89     1      169         0
89     1      169    111111
89     1      170         0
89     1      171         0
89     1      171         0
89     1      172    100003
89     1      173         0
89     1      174         0
89     1      175         0
89     1      176         0
89     1      177         0
89     1      178         0
89     1      179    100004
89     1      180         0
89     2      168    100006
89     2      169         0
89     2      170         0
89     2      171         0
89     2      172    100008

Note how I presented your example data in a data step with datalines, so it is easy for others to recreate the dataset. Please do so in the future; help us to help you.

Re: Add consecutive numbers in between of the dataset

chithra — Thu, 28 Mar 2019 09:59:36 GMT

Many thanks.

This is working

Re: Add consecutive numbers in between of the dataset

ErikLund_Jensen — Thu, 28 Mar 2019 10:24:38 GMT

Hi @chithra

Here is a slightly different way of doing just the same as Kurtbremser's code. It uses the point= option instead of firstobs=2. It is in no way better, I just post it because I want to promote use of the point= option, because it is so useful for look-ahead and -back, also in more complicated cases.

data want (drop= lastyear nextyear i); 
	set have; by id scn;
	nextrec = _N_ + 1;
	lastyear = year;
	output;
	if not last.scn then do;
		set have (keep=year rename=(year=nextyear)) point=nextrec;
		do i = lastyear + 1 to nextyear - 1;
			year = i;
			value = 0;
			output;
		end;
	end;
run;

Re: Add consecutive numbers in between of the dataset

chithra — Thu, 28 Mar 2019 11:38:46 GMT

just one modification to this.

The firt observation can be changed, it is not constant. that is if 168 is not the first observation, the first observation is missed, that was actually 167.

that number can be found out and stored in a macro or in some other way, that is possible.(may be that is the min of the whole table etc..)

THen how can we modify this?

Re: Add consecutive numbers in between of the dataset

Kurt_Bremser — Thu, 28 Mar 2019 11:59:05 GMT

In that case, you're better of using @ErikLund_Jensen 's method of lookahead, as it already uses by-processing:

%let start=167;

data want (drop=_year _value nextyear); 
  set have;
  by id scn;
  nextrec = _N_ + 1;
  if first.scn then do;
    _year = year;
    _value = value;
    do year = &start to year - 1;
      value = 0;
      output;
    end;
    value = _value;
    year = _year;
  end;
  output;
  if not last.scn then do;
    set have (keep=year rename=(year=nextyear)) point=nextrec;
    do year = year + 1 to nextyear - 1;
      value = 0;
      output;
    end;
  end;
run;

Re: Add consecutive numbers in between of the dataset

chithra — Fri, 29 Mar 2019 13:20:11 GMT

Thank you