dropping last observations

[Amalik]

Hi,

I want to drop the last observations from my data set but want to keep them only if the date is 29dec2017. I am using the following code, although it works perfectly fine but I am just unsure how to incorporate the date clause in it. 

data want(drop=count);
  set have;
  by permno descending date;
  if first.permno then count=0;
  count+1;
  if count>1;
run;

[cau83 · Accepted solution]

I added the code in CAPS below. Check the date first, then set count to zero if not that day.

data want(drop=count);
  set have;
  by permno descending date;
  IF DATE = "29DEC2017"d THEN COUNT=1;
  ELSE if first.permno then count=0;
  count+1;
  if count>1;
run;

[ChrisNZ]

Drop the last observation? How?

This:

data want(drop=count);
  set have;
  by permno descending date;
  if first.permno then count=0;
  count+1;
  if count>1;
run;

is the same is that:

data want;
  set have;
  by permno descending date;
  if first.permno then delete;
run;