Date:         Thu, 18 Oct 2007 12:38:28 -0400
Reply-To:     Dave Scocca <dave@SCOCCA.ORG>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Dave Scocca <dave@SCOCCA.ORG>
Subject:      Re: first business day of current month
Comments: To: BJMurphy <murphy.ben@GMAIL.COM>
In-Reply-To:  <1192723541.301546.214040@k35g2000prh.googlegroups.com>
Content-Type: text/plain; charset=us-ascii; format=flowed

--On 10/18/2007 9:05 AM -0700 BJMurphy wrote:

>         mmdd = substr(put(date,mmddyy6.),1,4);
>         if (weekday(date) in (1,7)) then date_type = 'w'; /* weekend */
>         else if
>                 (mmdd in ('0101','0704','1111','1225')) or
>                 (weekday(date) = 2 and
>                         ((mmdd in ('0102','0705','1112','1226') or

This leaves out the cases when the holiday falls on a Saturday and is
observed on the following Monday:  Mondays that are 0103, 0706, 1113, and
1227 are holidays.

> I can't decide the best way to figure out whether today was the first
> business day or not.

You can ignore most of the holidays, as they don't affect the beginning of
the month.

A date ("today") is the first business day of the month IF:

theDate=today() ;
theDay = day(theDate) ;
theMonth = month(theDate) ;
theWeekDay = weekDay(theDate) ;
isFirstBusinessDay = 0 ;

* A day is only a candidate for first-business-day if it is ;
* not a weekend and it is the fourth of the month or earlier ;
if ( (theDay le 4) and (theWeekDay not in (1, 7)) ) then do ;
   * A non-weekend first of the month is the first business day ;
   * Except in January and on Labor Day ;
   if theDay = 1 then do ;
      if theMonth not in (1, 9) then isFirstBusinessDay=1 ;
      else if theMonth=9 and theWeekDay ne 2
         then isFirstBusinessDay=1 ;
     end ;
   * A Monday second or third of the month is the first business day ;
   * Except in January and on Labor Day ;
   * A Tuesday second of the month in January or September is also ;
   * the first business day ;
   else if theDay in (2, 3) then do ;
      if ( theWeekDay=2 and theMonth not in (1, 9) ) or
         ( theWeekDay=3 and theMonth in (1, 9) )
         then isFirstBusinessDay=1 ;
     end ;
   * The fourth is only the first business day when it is Tues Jan 4 ;
   * or Tues Sep 4 ;
   else if theMonth in (1, 9) and theWeekday=3
      then isFirstBusinessDay=1 ;
  end ;

Dave