Convert ordered date to formal matlab date
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How to convert the following sequence of date to formal y/m/d or Matlab date format
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Accepted Answer
José-Luis
on 14 Oct 2014
Note that you'd still need the year. But if you know that then:
your_date = datenum(your_year-1, 12, 31, 0, 0, 0) + ordinal_day;
Ordinal_day goes from 1 to 365.
More Answers (3)
Kelly Kearney
on 14 Oct 2014
syear = 1900; % Year corresponding to first set of numbers
x = repmat(1:365, 1, 3)'; % Your data
yr = cumsum(x == 1) + (syear - 1);
dn = datenum(yr, ones(size(yr)), x); % datenumbers
If you want to format the date, you can use datestr:
>>datestr(dn(1))
ans =
01-Jan-1900
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dpb
on 14 Oct 2014
Edited: dpb
on 15 Oct 2014
Don't try to "convert", just create. Given the first year and length of the list, the date number vector would simply be
ystrt=2000; % or whatever
dn=datenum(ystrt,1,[1:length(dates)].',1);
datenum is smart enough to roll over the days by month and year including leap years.
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Sean de Wolski
on 14 Oct 2014
Or in R2014b you can do this with the new and improved datetime class:
datetime(2014,1,1:365,0,0,0)'
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dpb
on 15 Oct 2014
OK, so you were merely intending to emphasize the class as a class rather than some really enhanced functionality.
Wonder how the class implementation compares to "deadahead" array function performance-wise. Altho datenum is notoriously slow for all it's checking perhaps TMW has cleaned up a bunch of that and it's as fast or even faster...my machine here is limited and R2012b brings it to just barely tolerable performance so I've not tried the later revisions and I'm not at all eager to change UI.
Sean de Wolski
on 15 Oct 2014
The class does have some enhanced functionality, especially when it comes to plotting and time zones.
I haven't measured the performance of it. Maybe Peter will chime in.
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