count

[shahnaz]

Create a dataset to genrate the count of the number of student in a STUD dataset and also display records only if student count is 3 or more than 3

STUD Dataset :

STUDID         MARKS
1                     24
1                     24
1                     24
2                     24
2                     24
3                     24

O/P Requirement :

STUDID MARKS NEWVAR (U NEED TO CREATE)
1               24              1
1               24              2
1               24              3
2               24              1
2               24              2
3               24              1

can i get the output using proc freq procedure? (or) Which mehod is good to go?

[Kurt_Bremser]

Just use by processing and the correct syntax so newvar is automatically retained:

data want;
set have;
by studid;
if first.studid
then newvar = 1;
else newvar + 1; * this simple increment statement makes newvar a retained variable;
run;

[shahnaz]

Ohh Thank u soo much KurtBremser for the quick reply. And I have 1 more question for the same dataset:

Consider above student dataset and create a new dataset with only FIRST and LAST record of a student. If count =1 then no need to populate that record

Regards,

Shahnaz

[Kurt_Bremser · Accepted solution]

Determine the number of obs per studid in an intermediate step and then merge with the original dataset.

Note the use of the keep= option.

data have;
input studid marks;
cards;
1 24
1 24
1 24
2 24
2 24
3 24
;
run;

data int (keep=studid);
set have;
by studid;
if first.studid
then newvar = 1;
else newvar + 1;
if last.studid and newvar > 1;
run;

data want;
merge
  have
  int (in=a)
;
by studid;
if a and (first.studid or last.studid);
run;