MATLAB Answers


Converting a timetable to a matrix

Asked by AA
on 6 Apr 2018
Latest activity Answered by Peter Perkins
on 11 Apr 2018
Consider the following table
TimeStamp X1 X2 X3 X4
____________________ ______ ______ ______ ______
03-Jan-2005 01:08:00 1.9193 1.9193 1.9193 1.9193
03-Jan-2005 01:13:00 1.9193 1.9193 1.906 1.906
I tried converting it back to a matrix in order to get the following format:
732315 108 1.9193000 1.9193000 1.9193000 1.9193000
732315 113 1.9193000 1.9193000 1.9060000 1.9060000
Somehow I get an error with the following code:
numformat = datevec(TT.TimeStamp);
temp=regexp(TT.Timestamp,'\s+', 'split');
serialdates = datenum(char(datecol),formatfreak);
Error using regexp
The 'STRING' input must be either a char row vector, a cell array of char row vectors, or a string


on 6 Apr 2018
temp=regexp(ans,'\s+', 'split');
Looks like you pasted in a line from command window while testing; 'ans' is whatever it might happen to be in your code at the time you call regexp.
on 6 Apr 2018
I tried regexp(TT.TimeStamp,'\s+', 'split'); still getting the same error

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2 Answers

Answer by Walter Roberson
on 7 Apr 2018
Edited by Walter Roberson
on 7 Apr 2018
 Accepted Answer

TT.TimeStamp is in datetime() or duration() format for a timetable() object.
daynumbers = floor(datenum(TT.TimeStamp));
HM = hour(TT.TimeStamp)*100 + minute(TT.TimeStamp);
output = [daynumbers(:), HM(:), TT{:,:}];


on 7 Apr 2018
No, *100. You have 01:13:00 and you want to see 113 from that. hour() of this is 1, and minute() of this is 13. If you multiplied the 1 by 60 and added 13 you would get 73, number of minutes into the day, which is potentially a valid thing to want to see, but your example output requested 113 which is 1*100+13

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Answer by Peter Perkins
on 11 Apr 2018

AA, I guess Walter has answered your question, but I can't think of a reason why you would want to convert your table containing datetimes into those datenum+otherThing values. Maybe there's other code somewhere that expects that, but otherwise, it seems like an unnecessary headache.


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