Hello Stevenson, Jonathan, in a previous mail you wrote: > Hi, > > I've just had a problem related to the Date::Calc modules calculation of week >numbers, as some of my data suppliers are obviously using a different algorithm to >calculate week 1 of a year - they define dates which fall into week 1 of 2003 >according to Date::Calc as week 53 of 2002. > > I need to know the criteria for defining week 1 of a year according to Date::Calc to >check which data suppliers match, and which I need to create custom week number >generators for. From the documentation, I suspect it might be the week containing the >1si of January, with Monday defined as the first day of a week, but I can't find it >confirmed anywhere. Does anyone know what it uses?
I'm sorry if I forgot to include this information in the module's documentation. The algorithm (to be confirmed at http://www.engelschall.com/~sb/download/Date-Calc/DIN1355/) is defined as follows: 1) Monday is the first day of a week. 2) Is considered the first week (#1) of a year the week which contains at least 4 of the first 7 days in January. 2') Equivalent is: The first week is the one which contains the first Thursday of the year (because when Monday is the first day of a week, Thursday is the day in the middle of the week) and thus belongs to the year in question by more than a half. > Thanks for your help, > Jon Stevenson Hope this helps! :-) Best regards, -- Steffen Beyer <[EMAIL PROTECTED]> http://www.engelschall.com/u/sb/whoami/ (Who am I) http://www.engelschall.com/u/sb/gallery/ (Fotos Brasil, USA, ...) http://www.engelschall.com/u/sb/download/ (Free Perl and C Software)
