N° of the week from a date

[Dieter]

(11-06-2015 07:42 AM)ggauny@live.fr Wrote:  I would like explain why I use of week "0". In an old french text in calculating calendar, I saw this :

With all due respect for old French calendar texts: today ISO rules. And there is no week 0 defined in ISO 8601.

Quote:Si la première semaine de l’année est incomplète (c’est le cas six fois sur sept ; quand le premier janvier n’est pas un lundi), elle est numérotée 1 dès lors qu’elle a au moins quatre jours,

Correct.

Quote: 0 sinon.

Not correct.

(11-06-2015 07:42 AM)ggauny@live.fr Wrote:  But you have saw that in my Excel calendar I DON'T write week "0", it would be a no-sens, I agree. In my routine it was a shortcut to indicate that a day IS NOT in the first week but in the last week of year-1.

Well, exactly this is one of the tricky parts of the program: finding out whether the last week of the previous year is week 52 or 53. ;-)

(11-06-2015 07:42 AM)ggauny@live.fr Wrote:  I will update my routine to keep care of your comment, which is normal !

What do you think about the formula in the French text mentioned in the old thread from January? It looks quite straightforward and elegant, but I haven't checked it yet.

Dieter