MATLAB Answers

calculate week of year

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Richard
Richard on 18 Dec 2012
Answered: Steven Lord on 27 Mar 2020
I have an annual time series where measurements are recorded at hourly intervals:
StartDate = '2011-01-01 00:00';
EndDate = '2011-12-031 23:00';
DateTime=datevec(datenum(StartDate,'yyyy-mm-dd HH:MM'):60/(60*24):...
datenum(EndDate,'yyyy-mm-dd HH:MM'));
dat = 2+(20-2).*rand(size(DateTime,1),1);
I would like to calculate the mean 24 hour cycle for each week of the year i.e. for week 1, day of year 1 to 7 I want to calculate the average 00:00, 01:00,... and so on so eventually I will end up with 52, 24 hour series i.e. one for each week of the year. Matlab does have a function called 'weeknum' which returns the week number from a given seriel date number, however, this function is in the financial toolbox. Can anyone suggest an alternative methdo for finding week number?

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Accepted Answer

Jan
Jan on 18 Dec 2012
function weekOfYear = yourWeekNum(s)
% Get 1st of January of the year:
v = datevec(s);
v1 = v;
v1(:, 2:3) = 1;
v1(:, 4:6) = 0;
s1 = datenum(v1);
dayOfYear = s - s1;
weekOfYear = floor(dayOfYear / 7) + 1;
Please check this, because it is written in the editor and not tested.

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Richard
Richard on 18 Dec 2012
works great.
DWag
DWag on 27 Mar 2020
Yes it's great! And just a note for whoever uses it in the future, choose a date and double-check it to make sure it rounds to your needs. I rounded up isntead of having partial days.

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More Answers (1)

Steven Lord
Steven Lord on 27 Mar 2020
Since the original question was written, we introduced datetime. If you're representing your time and date data as a datetime, call week on your datetime with 'weekofyear' as the weekType input.

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