Creating a counter variable with mutiple conditional statements

[Kimbraun1]

Hi!

I'm trying to create a counter variable with multiple conditions. Please see below: the table includes the data in days and the counter I'm trying to program.

1.  This is all within a subject.  If first subject then start counter = 1.

2. if Days  >120 and the lag of the previous Day > 60 then counter =1 if this is the first observation meeting this criteria,

3. If Days >120 and lag of previous Day is <60 then don't add to the counter, rather this observation gets the same as the previous counter number.

4. If Days greater than 0 and LE 120 then +1 to the counter and all other observations <120 are the same counter value.

5. If Days is <0 then counter+1 for each instance. 

Thank you for any and all assistance.

Days	Counter
2514	1
141	2
99	3
54	3
0	3
-205	4
-290	5

[PaigeMiller]

Your rules are incomplete. If days > 120 and previous day = 60 exactly, you don't say what should happen. If days is exactly equal to zero, you don't say what should happen.

Also, your rules 1 and 2 seem to indicate that the counter starts at 1, then it can change, and then go back to 1 if rule 2 is satisfied, is this correct?

[Kimbraun1]

Hi Paige,

Thanks for your reply.  The 60 should be <= 60 and >= 0.  Yes, the counter starts at 1 each time, but will advance sequentially and not reset at 1 at any point.

I so appreciate your help and responsiveness.

[PaigeMiller]

data want;
    set have;
    by id;
    if first.id then counter=1;
    prev_days=lag(days);
    if days>120 and prev_day>60 then counter=1; /* This condition still doesn't make sense to me */
    else if days>=0 and days<=120 and prev_day>120 then counter+1;
    else if days<0 then counter+1;
run;