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Convert date text or serial date number to CDF formatted dates


E = cdfepoch(date)


E = cdfepoch(date) converts the date, specified by date, into a cdfepoch object. date must be valid date value represented by text, as returned by datestr, or a serial date number, returned by datenum. date can also be a cdfepoch object.

When writing data to a CDF file using cdfwrite, use cdfepoch to convert MATLAB® dates or serial date numbers to CDF formatted dates. The MATLAB cdfepoch object simulates the CDFEPOCH data type in CDF files.

To convert a cdfepoch object into a MATLAB serial date number, use the todatenum function.


Convert the current time in serial date number format into a CDF epoch object.

% NOW function returns current time as serial date number
dateobj = cdfepoch(now)
dateobj =
     cdfepoch object:
     11-Mar-2009 15:09:25

Convert the current time, which is returned by datestr in text form, into a CDF epoch object.

% DATESTR function returns text representing a date
dateobj2 = cdfepoch(datestr(now))
dateobj2 =
     cdfepoch object:
     11-Mar-2009 15:09:25

Convert the CDF epoch object into a serial date number.

dateobj = cdfepoch(now);
mydatenum = todatenum(dateobj)
mydatenum =

More About

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MATLAB Serial Date Number

A MATLAB serial date number represents the whole and fractional number of days from 0-Jan-0000 to a specific date. The year 0000 is merely a reference point and is not intended to be interpreted as a real year in time. The MATLAB serial date number calculates dates differently than CDF epochs.

CDF Epoch

A CDF epoch is the number of milliseconds since 1-Jan-0000.

Introduced before R2006a