Year conversion on figure wrong

If I read in a date, say 7/15/2017, but I read it in as 42931.00, when in MATLAB when I do this:

datetick('x', 'yyyy');

I get the year as 0117 instead of 2017?

Answer 1

[per isakson]

That's most likely because 42931.00 is an Excel date number, not a Matlab date number.

See Dates And Times In Excel. and https://se.mathworks.com/matlabcentral/answers/64198-matlab-datenum-to-excel-datetime#answer_75809

MATLAB date numbers start with 1 = January 1, 0000 A.D., hence there is a difference of 693960 relative to the 1900 date system

[Benjamin Cowen]

how do i convert it to matlab?

[Walter Roberson]

datetime 'convertfrom' 'excel'

[Benjamin Cowen]

when i do this:

t = datetime(date,'ConvertFrom','excel');

why does the x axis only show the begin and end date for this:

datetick('x', 'yyyy');

[Walter Roberson]

date is a function that returns a single character vector, that datetime then converts into a single datetime object. If you plot with that as your only data point then MATLAB invents start and end times.