I\'m trying to calculate the difference between two dates in \"weeks of year\". I can get the datetime object and get the days etc but not week numbers. I can\'t, of course,
You're a bit vague on what 'difference in weeks' means exactly. Is 6 days difference one week or zero ? Is eight days difference one week or two ?
In any case, why can't you simply find the difference in another unit (seconds or days) and divide by the appropriate amount, with your prefered rounding for weeks?