Hello everyone,
I am trying to calculate the length and number of interruptions between dates for each subject ID.
Here is the an example of what the data looks like in explorer:
usubjid |
startdate |
enddate |
12 |
2009-03-25 |
2010-10-26 |
12 |
2010-10-30 |
2011-01-30 |
12 |
2011-02-15 |
2011-03-16 |
13 |
2010-12-11 |
2011-01-13 |
13 |
2011-04-13 |
2011-07-30 |
For each subjectid, I would like to know the total number of interruptions and the total length of each interruptions.
Thanks for your help!
Donald S.
Try this:
data have;
format startdate enddate YYMMDD10.;
input usubjid startdate :YYMMDD10. enddate: YYMMDD10.;
datalines;
12 2009-03-25 2010-10-26
12 2010-10-30 2011-01-30
12 2011-02-15 2011-03-16
13 2010-12-11 2011-01-13
13 2011-04-13 2011-07-30
;
proc sort data = have;
by usubjid startdate;
run;
data want;
do until(last.usubjid);
set have; by usubjid;
call missing(daysInterruptions);
if not missing(lastDate) then do;
if startDate > lastDate then do;
nbInterruptions = sum(nbInterruptions, 1);
daysInterruptions = intck("DAY", lastDate, startDate);
end;
end;
output;
lastDate = endDate;
end;
drop lastDate;
run;
proc print data=want noobs; run;
Could you give example of your desired output based on the data you posted?
Yes Here is an example of the output, I also included how I would like to calculate the length:
usubjid |
startdate |
enddate |
# of interruptions |
Calc length |
Length of Interruption |
12 |
3/25/2009 |
10/26/2010 |
|
|
|
12 |
10/30/2010 |
1/30/2011 |
1 |
10/30/2010 - 10/26/2010 |
4 |
12 |
2/15/2011 |
3/16/2011 |
2 |
2/15/2011 - 1/30/2011 |
16 |
13 |
12/11/2010 |
1/13/2011 |
|
|
|
13 |
4/13/2011 |
7/30/2011 |
1 |
4/13/2011 - 1/13/2011 |
90 |
I hope this made things a little clearer,
Thank you,
Donald S.
Try this:
data have;
format startdate enddate YYMMDD10.;
input usubjid startdate :YYMMDD10. enddate: YYMMDD10.;
datalines;
12 2009-03-25 2010-10-26
12 2010-10-30 2011-01-30
12 2011-02-15 2011-03-16
13 2010-12-11 2011-01-13
13 2011-04-13 2011-07-30
;
proc sort data = have;
by usubjid startdate;
run;
data want;
do until(last.usubjid);
set have; by usubjid;
call missing(daysInterruptions);
if not missing(lastDate) then do;
if startDate > lastDate then do;
nbInterruptions = sum(nbInterruptions, 1);
daysInterruptions = intck("DAY", lastDate, startDate);
end;
end;
output;
lastDate = endDate;
end;
drop lastDate;
run;
proc print data=want noobs; run;
Hello PGStats, your code worked exactly the way I needed! Thank you very much! I have never seen an until function before, but it makes things MUCH eaier than the do loops I was trying to do before! Glad to learn something new!
Just a remark: There is no "UNTIL function", but only the DO UNTIL statement, which marks the beginning of a loop in which statements are executed repetitively until a condition is true. This exit condition is written in parentheses after the UNTIL keyword -- a notation which in fact resembles that of a function call.
PG used this DO UNTIL loop in a special way:
do until(last.varname); set dataset; by varname; ... end;
This and similar constructs are known as "DOW loops." Here's an introductory paper on this useful, somewhat advanced SAS programming technique: http://www2.sas.com/proceedings/sugi28/099-28.pdf. There are more on the web, just search for "DOW loop" SAS.
Please try this alternative method
data want;
set have;
by usubjid;
prevdate=lag(enddate);
if first.usubjid then prevdate=.;
Length_of_Interruption=intck('day',prevdate,startdate);
format prevdate date9.;
run;
data have;
infile cards expandtabs truncover;
format startdate enddate YYMMDD10.;
input usubjid startdate :YYMMDD10. enddate: YYMMDD10.;
datalines;
12 2009-03-25 2010-10-26
12 2010-10-30 2011-01-30
12 2011-02-15 2011-03-16
13 2010-12-11 2011-01-13
13 2011-04-13 2011-07-30
;
proc sort data = have;
by usubjid startdate;
run;
data want;
set have;
by usubjid ;
lag_enddate=lag(enddate) ;
if first.usubjid then group=0;
else if startdate gt lag_enddate then do;
group+1;
n=group;
dif=startdate - lag_enddate;
end;
drop lag_enddate group;
run;
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