addtodate: unexpected result when adding years

Hi all,

I'm having an issue with addtodate.m. The example:

addtodate(1, 2014, 'year')

ans =

       -734501

is not what I expected... Does anyone know what's going on?

Notes: I'm trying to use addtodate to sanitize a date vector

datevec_unsan = [2014, 1, 1, 40, 0, 0];  % there aren't 40 hours in a day...
types = {'year', 'month', 'day', 'hour', 'minute', 'second'};
tstamp = 0;
for i = 1:6
    tstamp = addtodate(tstamp, datevec_unsan(i), types{i});
end
datevec_sanitized = datevec(tstamp);

Answer 1

[the cyclist]

I was unaware of this handy function before, but this definitely seems like a bug. The result of

datestr(addtodate(1,2014,'year'))

is '01-Jan-7986', while

datestr(addtodate(1,-2014,'year'))

gives '01-Jan-2014' (which I am guessing is what you expected for your answer originally). Adding just a day or a month seems to work fine, though.

I am about to head out the door, so I can't dig in right now, but you could try

edit addtodate

to poke into the function and see what's going on. I suggest you fill out a bug report, unless someone here points out something obvious that you and I are misunderstanding!

[Andrew]

Thanks for looking at this. addtodate uses addtodatemx so I don't think we can look at the source sadly

Answer 2

[Star Strider]

MATLAB will do the correction for you. I don’t know the result you want, but this works:

datevec_unsan = [2014, 1, 1, 40, 0, 0]
x = datenum(datevec_unsan);
datevec_new = datevec(x)

produces:

datevec_unsan =

       2014     1     1    40     0     0

datevec_new =

       2014     1     2    16     0     0

[Andrew]

Good idea - its even in the datenum documentation that it supports it! And it saves me putting in correction for 1 based days in my original code.

[Star Strider]

Thanks!

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