date conversions from yyyydddhhmmss to the number format

I have a different date format that I need to convert to the "number" format. What I have is

Data 2018:335:00:00:11 4.4960559400000193E+00 1.1337406300000055E+00

I have many lines of txt. How do I convert this one? Columns 3 & 4 are data taged at the time. The format seems to be yyyy.ddd.hh.mm.ss

Answer 1

[Adam Danz]

Assuming you've already isolated the datetime strings,

% Convert string to datetime
dtstr = '2018:335:00:00:11'; 
dt = datetime(dtstr,'InputFormat', 'u:D:HH:mm:ss'); 

% if you want that in serial date format
n = datenum(dt); 

If you need help isolating the strings, leave a comment (hint: regexp).

Note that the string format uses "D" for day-of-year and "u" for ISO-year in place of the Gregorian year (y).