Convert ordered date to formal matlab date

How to convert the following sequence of date to formal y/m/d or Matlab date format

Answer 1

[José-Luis]

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.

[dpb]

What about leap years? OP shows multiple years possible in his listing w/o a starting year hint. Of course, he may be ignoring them...

[José-Luis]

I assumed that if it was a leap year it'd say 366, but your point is valid.

Answer 2

[Kelly Kearney]

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

Answer 3

[dpb]

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.

Answer 4

[Sean de Wolski]

Or in R2014b you can do this with the new and improved datetime class:

datetime(2014,1,1:365,0,0,0)'

[dpb]

That's just one year, though, right?

[Sean de Wolski]

Yeah, just 2014. But there's no reason it couldn't be multiple years.

[dpb]

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]

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.