MATLAB Answers


How to convert date by changine date format from text file?

Asked by Dogan Deniz Karadeniz on 25 Jun 2019
Latest activity Edited by Kojiro Saito on 26 Jun 2019
I'd like to convert date according to first three column as day-month-year hour:minute:second.
  • A column: Year
  • B column: Day of the year
  • C column: Hour
I tried to do it, not achieving.


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2 Answers

Answer by Kojiro Saito on 25 Jun 2019
Edited by Kojiro Saito on 26 Jun 2019
 Accepted Answer

Simply, you can utilize table's functioinalities.
t = readtable('test5.txt');
% Create datetime and display as "day-month-year hour:minute:second" format
dt = datetime([t.Var1 ones(height(t), 1) t.Var2 t.Var3 zeros(height(t), 1) zeros(height(t), 1)], 'Format', 'dd-MM-yyyy HH:mm:ss');
% Insert datetime variable to the table as "datestr" column
t.datestr = dt;
% Write a table as a file
writetable(t, 'output.txt')
Based on your comment, the following is what you want. removevars and movevars were introduced in R2018a.
t = readtable('test5.txt');
% Convert to datetime
dt = datetime([t.Var1 ones(height(t), 1) t.Var2 t.Var3 zeros(height(t), 1) zeros(height(t), 1)]);
% Insert datetime variables to original table
t.datestr = datetime(dt, 'Format', 'dd-MM-yyyy');
t.timestr = datetime(dt, 'Format', 'HH:mm:ss');
% Delete column 1 to 3
T2 = removevars(t, 1:3);
% Move datestr and timestr to the first and second columns
T2 = movevars(T2, {'datestr', 'timestr'}, 'Before',1);
% Write table as a tab separated file without headers
writetable(T2, 'output.txt', 'WriteVariableNames', false, 'Delimiter', 'tab')


I think I didn't explain myself clearly.
Output should be as follow
29-06-2012 00:00:00 30 25 21.2
I've updated the answer.

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Answer by Himanshu Rai on 25 Jun 2019

Try this function, it accepts three vectors corresponding to year, day and hour
function Dt = conv(Year, Day, Hour)
Dt = datetime(Year, 1, 1) + Day - 1 + hours(Hour);


I will give an example
Year = 2000:2020; % your year vector
Day = 20:40 % your day vector
Hour = 0:20 % your hour vector
conv(Year, Day, Hour) % calling the function with the arguments
If you want to read data from the file, use this link - textscan. However note that this was not what was specified in your question. If you want something else please specify it clearly in your question.
Sorry about that. Indeed, I need to write output other columns together in the text file.

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