How to filter data?
3 views (last 30 days)
Show older comments
Dear all,
I want to filter a matrix by its date vector. The datevector has the format: dd.mm.yyyy HH:MM:SS. I want to sum up all the data with the same month and year. How can I do that?
0 Comments
Accepted Answer
Jan
on 16 Jan 2013
dateAsString = {'31.02.2013 11:22:33'; '31.05.2013 11:22:33'}
dateAsVector = datevec(datestr, 'dd.mm.yyyy HH:MM:SS');
yearAndMonth = 100 * dateAsVector(:, 1) + dateAsVector(:, 2);
Now you get values like [201302, 201305] and summing can be done by accumarray directly.
2 Comments
Walter Roberson
on 16 Jan 2013
You would probably not want to use those values as direct subscripts into accumarray: you would probably want to unique() them and use the indices. Otherwise your array is going to end up being up to 240000 long with not many entries used.
Jan
on 16 Jan 2013
You are right, Walter, and even for a FOR loop approach using the indices obtained by UNIQUE is better.
More Answers (0)
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!