INTNX using interval R445MON not giving expected results

[PaigeMiller]

Here's my code

data a;

    today=mdy(1,1,2015);

    do month=1 to 12;

        start_of_month=intnx('r445mon',today,month-1,'s');

        end_of_month=intnx('r445mon',today,month-1,'e');

        output;

    end;

    format start_of_month end_of_month date7.;

    drop today;

run;

proc print data=a noobs;

run;

which produces the following output, note that I would have expected the end_of_month to be one day before the start of the next month, but month 1 ends on 25JAN15 and month 2 starts on 29JAN15. Why is that? How can I fix this?

	start_	end_of_
month	of_month	month

1	01JAN15	25JAN15
2	29JAN15	22FEB15
3	26FEB15	29MAR15
4	02APR15	26APR15
5	30APR15	24MAY15
6	28MAY15	28JUN15
7	02JUL15	26JUL15
8	30JUL15	23AUG15
9	27AUG15	27SEP15
10	01OCT15	25OCT15
11	29OCT15	22NOV15
12	26NOV15	03JAN16

[SASKiwi · Accepted solution]

If you read the definition of the interval: R455MON:

Months that start on the 1st, 5th,9th, 14th, 18th,22nd, 27th, 31st,35th, 40th, 44th,and 48th Monday of the year. The 1st Monday is the Monday on or immediately preceding January 4th.

If you start your program on the 1st Monday of the year which is 29 Dec 2014 then you will get the expected result with the S option which means SAME not start. If you start with another date then use B for BEGINNING:

data a;

  today=mdy(1,1,2015);

  do month=0 to 11;

    start_of_month=intnx('r445mon',today, month,'b');

    end_of_month=intnx('r445mon',today, month,'e');

    output;

    end;

    format start_of_month end_of_month date9.;

run;

proc print data=a noobs;

run;

[PaigeMiller]

Okay, thank you, I see my silly error.