Given year and month, how to formate a date variable?

[Elaine_S]

In my sample of data, I have firm, year, month and price variables. I would like to create a new variable with year-month-day in any sas format, where day is the last business day (or last day) of the given year month. Can anyone help me on it plz? Thanks

data tmp1;
input year firm$ month$ price;
datalines;

2004 AE0006 m1 8.2
2004 AE0006 m2 8.5
2004 AE0006 m3 8.2
2004 AE0006 m4 8.3
2004 AE0006 m5 8.4
2004 AE0006 m6 8.5
2004 AE0006 m7 8.6
2004 AE0006 m8 8.7
2004 AE0006 m9 8.8
2004 AE0006 m10 8.9
2004 AE0006 m11 9
2004 AE0006 m12 9.1
2005 AE0006 m1 9.2
2005 AE0006 m2 9.3
2005 AE0006 m3 9.4
2005 AE0006 m4 9.5
2005 AE0006 m5 9.6
2005 AE0006 m6 9.7
2005 AE0006 m7 9.8
2005 AE0006 m8 9.9
2005 AE0006 m9 10
2005 AE0006 m10 10.1
2005 AE0006 m11 10.2
2005 AE0006 m12 10.3

run;

Here is what I expect:

date                     price
31-Jan-2004         8.2
29-Feb-2004         8.5
31-Mar-2004         8.2
30-Apr-2004        8.3
31-May-2004       8.4
30-Jun-2004        8.5
31-Jul-2004         8.6
31-Aug-2004        8.7
30-Sep-2004       8.8
31-Oct-2004        8.9
30-Nov-2004       9
31-Dec-2004       9.1
31-Jan-2005       9.2
28-Feb-2005       9.3
31-Mar-2005       9.4
30-Apr-2005        9.5
31-May-2005       9.6
30-Jun-2005       9.7
31-Jul-2005        9.8
31-Aug-2005      9.9
30-Sep-2005     10
31-Oct-2005     10.1
30-Nov-2005     10.2
31-Dec-2005     10.3

[s_lassen · Accepted solution]

Something like this?

data want;
  set tmp1;
  last_date=intnx('month',mdy(input(substr(month,2),2.),1,year),0,'E');
  select(weekday(last_date));
    when(1) last_working_day=last_date-2; /* Sunday */
    when(7) last_working_day=last_date-1; /* Saturday */
    otherwise last_working_day=last_date;
    end;
  format last_date last_working_day date9.;
run;

You wrote that you want the last business date - I put in a check for the weekday, and put the result in last_working_day. But you may have to check for some national holidays as well.