calculating the difference between 2 dates

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antonet on 25 May 2012
Commented: Rosanna on 11 Oct 2018
Dear all,
I would like to calculate the difference between the dates say,
20/11/08 and 12/10/2011 in weeks and in months
cheers

Walter Roberson on 25 May 2012
numdays = datenum('12/10/2011') - datenum('20/11/08');
numweeks = numdays / 7; %and round() or floor() or ceil() as appropriate
numdaysvec = datevec(numdays);
nummonths = numdaysvec(1) * 12 + numdaysvec(2) - 1;
Note that you might have to give datenum() a hint as to whether the first date is the 11th month of 2008 or the 8th month of 2011.
Also, I used a shortcut here of converting the day offset as if it was a date relative to "year 0". MATLAB has weak leap-year routines that believe that "year 0" was a leap year. More accurate would be to datevec() the original dates and do modular arithmetic.
Oh yes, you also need to decide whether dates in the same month count as "0 months" or as "1 month" for your purposes.
antonet on 26 May 2012
Thank you!

Andy on 13 Mar 2018
Edited: Andy on 13 Mar 2018
there's something better now since 2014 release I believe:
w = between(startRange,endRange,'weeks')
y = between(startRange,endRange,'years')
m = between(startRange,endRange,'months')
Rosanna on 11 Oct 2018
Hi all I have to compute the occurrence time (days from the starting date) of a large number (eg N=1000) of events, for which I have the Year, Month, Day, Hour, Minute in numerical format (eg 2008, 05, 23, 08, 34). How can I proceed? Thanks Rosanna