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Subject: Re: [office] YEARFRAC, etc.
On Mon, 2008-04-14 at 19:30 -0400, Patrick Durusau wrote: > > 2) The definition for the European 30/360 function doesn't make sense. > > It is grammatical, but still gibberish. The text is "For months with > > 31 days, all dates with a day value of 31 are changed to day 30, > > including 28 and 29 February." > > > Well, inartfully worded, I suspect: "All months have 30 days." covers > all the cases. Yes? No, it doesn't. If you want to calculate as if you have 30 days per month, you need to say what to do if a date refers to day 31 in a month. Apparently this is supposed to be considered the same date as day 31. Now what happens in February. I would guess that it is intended that the last day of February is also supposed to be considered as day 30 (so in a leap year February 29th is changed to Feb 30 before calculations and in a non-leap year Feb 28 is changed to Feb 30. What about Feb 28 in a leap year? Clearly it doesn't make sense to change it to February 30. So we are just guessing... > Looks like someone got tied up in how many days each > month has. Really irrelevant if you want to say that all months have 30 > days. Just say that, full stop. How an application treats a particular > date is determined by that rule, every month has 30 days. What more need > be said? > > If it is Feb 28, then we have Feb. 30. Why? The last day of that month may be February 29. Since you are adding days to February it is unlikely that it is intended to identify days in that month. > If it is Feb 29, then it is Feb > 30. > If it is May 31, it is May 30. If it is June 30, well, it is June > 30. What is unclear about that? > > But note that all you have to do is write the rule the simplest way > possible. It is when people try to be clever that stuff goes wrong. > > *NOTE* I don't know if that is "correct" or not but will check. Note: that exactly is the problem. (Personally as indicated above I don't think that your interpretation is what is really meant. (Well, at least I think what yuou wrote is what is meant. I wouldn't be surprise if you meant what I think the rule is intended to say.) Have a nice day (or evening) Andreas -- "Liberty consists less in acting according to one's own pleasure, than in not being subject to the will and pleasure of other people. It consists also in our not subjecting the wills of other people to our own." Rousseau Prof. Dr. Andreas J. Guelzow Dept. of Mathematical & Computing Sciences Concordia University College of Alberta