Reading a large csv and converting to timetable

조회 수: 7 (최근 30일)
Louise Wilson
Louise Wilson 2020년 4월 30일
댓글: Louise Wilson 2020년 8월 26일
I have a large .csv (7179x72001) 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');
  댓글 수: 4
Louise Wilson
Louise Wilson 2020년 4월 30일
I have just tried this:
thetable=readtable(fullfile(foldername,'001Noises_5103_PSD_1sHammingWindow_50%Overlap_output.csv'));
datetime(thetable.Var1,'ConvertFrom','datenum');
head(thetable)
This doesn't give any errors but the contents of the first column remain as datenums.
Louise Wilson
Louise Wilson 2020년 4월 30일
Ah, I see now that it should be this:
tt.Var1=datetime(tt.Var1, 'ConvertFrom','datenum');
This works! Thanks for your help!!

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Louise Wilson
Louise Wilson 2020년 4월 30일
tt.Var1=datetime(tt.Var1, 'ConvertFrom','datenum');
  댓글 수: 2
darova
darova 2020년 4월 30일
You can accept your own answer so it could help someone else
Louise Wilson
Louise Wilson 2020년 8월 26일
Thanks!

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