how to combine date and time

So i have my data file attached

want to combine the data and time

then using the combined datetime produce different temptime graphs of diff days

Answer 1

[Star Strider]

In theory at least, datetime should be able to do this seamlessly using the timeofday function for the seconds. In practice, it cannot do it at all, at least when I tried it, so I resorted to datenum to do the necessary arithmetic to combine the dates and times.

Try this:

D = readtable('data.txt','ReadVariableNames',1);
DNS = datenum([zeros(size(D,1),5) D{:,2}]);
DND = datenum(compose('%s',D{:,1}),'dd/mm/yyyy');
DateTime = datetime(DND + DNS, 'ConvertFrom','datenum');

When I looked at the results with:

Check = DateTime([1:20:1000]);

it seemed to be converting them correctly. I may have gotten the days and months reversed, since the date format is not obvious. Correct that if necessary by changing ‘'dd/mm/yyyy'’ to ‘'mm/dd/yyyy'’.

The compose call takes a while, so in the interests of speed, save ‘DateTime’ to a .mat file to load quickly when you want to use it later.