```Date: Thu, 24 May 2001 06:43:49 -0700 Reply-To: Pete Lund Sender: "SAS(r) Discussion" From: Pete Lund Subject: Re: week number counting? Comments: To: Arjen.Raateland@vyh.fi In-Reply-To: <3B0CCD5C.858DF77A@vyh.fi> Content-Type: text/plain; charset="us-ascii" Arjen- As you know, INTNX will always return the first date of the period you reference. With INTNX('WEEK',,0) you'll get the first day of the week that contains Jan 1. Using WEEK.5 gives you the Thursday of that week. However, as you found, if the first of January is on a Friday or Saturday then the Thursday of that week will be in the previous year. It sounds like what you really need is an offset for the SAS week to account for that. If you're using V8 you can use a PICTURE format to get the week number and use that to create an offset to use in your INTNX function. proc format; picture WeekNum low - high = '%U' (datatype=date); run; data _null_; baseweek = put(intnx('WEEK.5',"01JAN&year"d,0),WeekNum.) ne '0'; firstthursday=put(intnx('WEEK.5',"01JAN&year"d,BaseWeek), eurdfdd10.); put baseweek= firstthursday=; run; Now, BASEWEEK will be an offset you can use in your "first thursday" calculation. Let's see how it works: - INTNX('WEEK.5',"01JAN&YEAR"d,0) will return the Thursday of the first week of the year (see above) - The WeekNum. format will return the week number of that date - either 0 or 52 (if the Thursday is in the previous year) - Now, just compare that result to '0' - if it is '0' we're in the right year and the "ne 0" will return 0. If it's 52, the "ne 0" will return 1. So, we now have an offset value that can be used in your original FirstThursday calculation. Just replace the "0" with "BaseWeek" and you should be the date of the first Thursday that's really in the year in question. You could also create a macro variable containing the BaseYear value and you wouldn't have to recreate it over and over: %let BaseWeek = %eval(%sysfunc(intnx(week.5,"01jan&year"d,0),WeekNum.) ne '0'); Then, your datastep line would be: firstthursday=put(intnx('WEEK.5',"01JAN&year"d,&BaseWeek), eurdfdd10.); Hope this helps- ---------------------------------------------------------------------------- --- Pete Lund Northwest Crime and Social Research 313-D Fifth Ave SE Olympia, WA 98501 (360) 528-8970 - voice (360) 280-4892 - cell (360) 570-7533 - fax pete.lund@nwcsr.com www.nwcsr.com ---------------------------------------------------------------------------- --- -----Original Message----- From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU]On Behalf Of Arjen Raateland Sent: Thursday, May 24, 2001 1:59 AM To: SAS-L@LISTSERV.UGA.EDU Subject: week number counting? In Finland the weeks of the year are numbered starting with the week that has the first thursday of the new year. SAS seems to number weeks differently, as seen from the following: %let year=1998; data _null_; firstthursday=put(intnx('WEEK.5',"01JAN&year"d,0), eurdfdd10.); put firstthursday; run; %let year=1999; data _null_; firstthursday=put(intnx('WEEK.5',"01JAN&year"d,0), eurdfdd10.); put firstthursday; run; 2132 %let year=1998; ... 01.01.1998 2139 %let year=1999; ... 31.12.1998 The latter date is in the previous year ... I'm looking for a formula that produces the date of Wednesday in the week with a particular week number (according to the above definition), but I can't seem to figure it out. Help will be appreciated. TIA, -- Arjen Raateland Finnish Environment Institute SAS Support phone +358 9 4030 0350 ```

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