Hi,
I have a long series of data, recorded daily from Monday to Friday. I'd like to add a variable that numbers consecutive weeks - it will equal 1 for the first 5 obs, 2 for observations 6-10 etc. (like in the example below). How to do it?
data have;
input date :yymmdd10.;
format date yymmdd10.;
datalines;
2020-01-06
2020-01-07
2020-01-08
2020-01-09
2020-01-10
2020-01-13
2020-01-14
2020-01-15
2020-01-16
2020-01-17
2020-01-20
2020-01-21
2020-01-22
2020-01-23
2020-01-24
;
run;
data want;
input date :yymmdd10. week_no;
format date yymmdd10.;
datalines;
2020-01-06 1
2020-01-07 1
2020-01-08 1
2020-01-09 1
2020-01-10 1
2020-01-13 2
2020-01-14 2
2020-01-15 2
2020-01-16 2
2020-01-17 2
2020-01-20 3
2020-01-21 3
2020-01-22 3
2020-01-23 3
2020-01-24 3
;
run;
Best
How about
data have;
input date :yymmdd10.;
format date yymmdd10.;
datalines;
2020-01-06
2020-01-07
2020-01-08
2020-01-09
2020-01-10
2020-01-13
2020-01-14
2020-01-15
2020-01-16
2020-01-17
2020-01-20
2020-01-21
2020-01-22
2020-01-23
2020-01-24
;
data want;
set have;
if mod(_N_, 5) = 1 then weekno + 1;
run;
w = week(date);
How about
data have;
input date :yymmdd10.;
format date yymmdd10.;
datalines;
2020-01-06
2020-01-07
2020-01-08
2020-01-09
2020-01-10
2020-01-13
2020-01-14
2020-01-15
2020-01-16
2020-01-17
2020-01-20
2020-01-21
2020-01-22
2020-01-23
2020-01-24
;
data want;
set have;
if mod(_N_, 5) = 1 then weekno + 1;
run;
Anytime. My code is a direct solution to your specific problem. I must address, that you should take advatage of the week() function if applicable.
I guess I have concerns about both of the above solutions, as it could be possible that they fail in certain situations. In particular, relying on _N_ requires that there always be five days listed for each week; if a day isn't listed because its a holiday, then this method fails. The WEEK function works fine within a year, but if the data set is 53 or more weeks long, then (for example), Jan 3 2020 and Jan 3 2021 would be the same week.
I would use the INTCK function to determine the number of weeks after the first date.
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