MATLAB Answers

How can I convert a datetime vector to cell??

225 views (last 30 days)
Adriano
Adriano on 17 Nov 2016
Commented: Peter Perkins on 18 Nov 2016
hi all,
I have a vector of 4000 dates like:
25/07/1996;
26/07/1996;
29/07/1996;
30/07/1996;
31/07/1996;
01/08/1996;
02/08/1996;
05/08/1996;
06/08/1996;
07/08/1996;... and so on
Now, they are in datetime format. My goal is to insert the dates like rows names into a table. For example:
Age Height Weight BloodPressure
___ ______ ______ _____________
25/07/1996 38 71 176 124 93
26/07/1996 43 69 163 109 77
I know that the rows names of a table must be cell inputs. Thus, how can I do it? Thanks a lot!

  0 Comments

Sign in to comment.

Accepted Answer

Walter Roberson
Walter Roberson on 17 Nov 2016
Edited: Walter Roberson on 17 Nov 2016
Example:
YourTable = array2table((1:6).')
temp = cellstr( datestr(732430:732435) );
YourTable.Properties.RowNames = temp;

  3 Comments

Adriano
Adriano on 17 Nov 2016
It doesn`t work. Remeber, I need the rows names in the format dd/mm/yyyy and not a number!. Thanks.
Walter Roberson
Walter Roberson on 17 Nov 2016
YourTable = array2table((1:6).')
temp = cellstr( datestr(732430:732435, 'dd/mm/yyyy') );
YourTable.Properties.RowNames = temp;
I think you did not notice the datestr()

Sign in to comment.

More Answers (2)

Guillaume
Guillaume on 17 Nov 2016
Rather than using obsolete datestr, simply convert the datetime with char (which will use the Format of the datetime:
array2table(somematrix, 'RowNames', cellstr(char(datetimevector)))
Note that R2016b introduces the timetable that makes this even simpler:
array2timetable(somematrix, 'RowTimes', datetimevector)

  1 Comment

Peter Perkins
Peter Perkins on 18 Nov 2016
You can even go directly to a cellstr, without char in the middle:
array2table(somematrix, 'RowNames', cellstr(datetimevector))

Sign in to comment.


Peter Perkins
Peter Perkins on 18 Nov 2016
Adriano, row names are really convenient when you want to use them for subscripting. But in this case, you need to consider that you are taking a datetime vector and turning it into text. So you lose all the calendar arithmetic that datetime provides, and you will no longer be able to do things like
T(T.Date > '1-Jan-2016',:)
that you would be able to do if you put the datetime vector into your table as a variable rather than as the row names. It depends on what you want to do.
As Guillaume pointed out, the new-for-R2016b timetable type kind of gives you the best of both worlds, a timetable's "row names" are actually row times, stored as either datetimes or durations.

  0 Comments

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!