topic Re: Restart and Continue Sequence (i.e., Time) Based on Three Variables in SAS Programming

Restart and Continue Sequence (i.e., Time) Based on Three Variables

PhillipSherlock — Mon, 18 Jul 2016 19:01:45 GMT

Below is an example of the data I would like to create. I have the Study, Case and Phase variables. I need help creating the Time variable. Time must restart every time Phase changes from 0 to 1. However, if Phase returns to 0 or 1 for the same Case in the same Study, Time should continue counting from the previous instance of that particular Phase.

Study	Case	Phase	Time
1	1	0	1
1	1	0	2
1	1	1	1
1	1	1	2
1	1	0	3
1	1	0	4
1	1	1	3
1	1	1	4
1	2	0	1
1	2	0	2
1	2	1	1
1	2	1	2
1	2	0	3
1	2	0	4
1	2	1	3
1	2	1	4
2	1	0	1
2	1	0	2
2	1	1	1
2	1	1	2
3	1	0	1
3	1	0	2
3	1	1	1
3	1	1	2
3	1	0	3
3	1	0	4
3	1	1	3
3	1	1	4
3	2	0	1
3	2	0	2
3	2	1	1
3	2	1	2
3	2	0	3
3	2	0	4
3	2	1	3
3	2	1	4

Thank you for your help.

Re: Restart and Continue Sequence (i.e., Time) Based on Three Variables

TomKari — Mon, 18 Jul 2016 19:28:49 GMT

data want;

set have;

retain Time _Time;

drop _:;

by Study notsorted Case notsorted Phase notsorted;

if first.Case

then do;

Time = 1;

_Time = Time;

end;

else if first.Phase then

if Phase = 0 then do;

Time = Time + 1;

_Time = Time;

end;

else do;

Time = _Time;

end;

else Time = Time + 1;

run;

Re: Restart and Continue Sequence (i.e., Time) Based on Three Variables

PGStats — Mon, 18 Jul 2016 20:12:58 GMT

Please explain this particular sequence:

Study

Case

Phase

Time

1	1	0	3
1	1	0	4
1	1	1	3
1	1	1	4

Why does Time go back to 3?

Re: Restart and Continue Sequence (i.e., Time) Based on Three Variables

stat_sas — Mon, 18 Jul 2016 20:27:10 GMT

Hi,

Please try this. You need to create id variable to bring back data in its original form. As per desired output you need to sort it by phase variable that will bring data in a sequence (0s and 1s together) and from there iterate time variable. Once this is done you can bring back data in original shape by sorting it id variable.

data have;
input Study Case Phase;
id=_n_;
datalines;
1 1 0
1 1 0
1 1 1
1 1 1
1 1 0
1 1 0
1 1 1
1 1 1
1 2 0
1 2 0
1 2 1
1 2 1
1 2 0
1 2 0
1 2 1
1 2 1
2 1 0
2 1 0
2 1 1
2 1 1
3 1 0
3 1 0
3 1 1
3 1 1
3 1 0
3 1 0
3 1 1
3 1 1
3 2 0
3 2 0
3 2 1
3 2 1
3 2 0
3 2 0
3 2 1
3 2 1
;

proc sort data=have;
by Study Case Phase;
run;

data want;
set have;
by Study Case Phase;
if first.study or first.case or first.Phase then Time=0;
Time+1;
run;

proc sort data=want out=want(drop=id);
by id;
run;

Re: Restart and Continue Sequence (i.e., Time) Based on Three Variables

PhillipSherlock — Mon, 18 Jul 2016 20:30:30 GMT

That is the second instance where Case 1 from Study 1 is in Phase 1. The last time point from the first instance of Case 1 from Study 1 in Phase 1 was Time = 2. Thus, in the second instance of Case 1 from Study 1 where Phase = 2, Time will continue starting with 3.

Re: Restart and Continue Sequence (i.e., Time) Based on Three Variables

Ksharp — Tue, 19 Jul 2016 05:28:45 GMT

Of course. I would not miss such question. Assuming I know what you are looking for .

data have;
input Study Case Phase;
datalines;
1 1 0
1 1 0
1 1 1
1 1 1
1 1 0
1 1 0
1 1 1
1 1 1
1 2 0
1 2 0
1 2 1
1 2 1
1 2 0
1 2 0
1 2 1
1 2 1
2 1 0
2 1 0
2 1 1
2 1 1
3 1 0
3 1 0
3 1 1
3 1 1
3 1 0
3 1 0
3 1 1
3 1 1
3 2 0
3 2 0
3 2 1
3 2 1
3 2 0
3 2 0
3 2 1
3 2 1
;
run;
data want;
 set have;
 by Study Case;
 retain temp found initial;
 lag_Phase=lag(Phase);
 if first.Case then do;
  n=0;temp=0;initial=0;found=0;
 end;
  else if Phase=1 and lag_Phase=0 then do;
   n=0;
   if found then initial=temp;
  end;
   else if Phase=0 and lag_Phase=1 then do;temp=n;found=1;end;
   n+1;
 time=sum(n,initial); 
 drop n temp found initial lag_Phase;
run;