MATLAB: Reading a large csv and converting to timetable

Question

I have a large .csv (7179×72001) where the first column is filled with datenums and the remaining columns are numerical values. The only way I have been successful in reading this data is by using csvread() and it usually takes about 20 minutes.

I have a second .csv which contains the same values but in datetime format and I would like to compare the two.

Is it possible to convert the first column in the large file so that the values are datetimes, and then in turn convert this to a timetable?

I can do this but I only want to convert the first column, not the whole dataframe:

newtable=datetime(dataframe, 'ConvertFrom', 'datenum');

Answer 1

tt.Var1=datetime(tt.Var1, 'ConvertFrom','datenum');