Why wont unique function eliminate duplicate rows in timetable?

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Nicholas Gaug
Nicholas Gaug 2022-2-23
评论： Kevin Johnson 2022-4-19
I have a table of a large data set that contains many duplicate time and am trying to remove them. The documentation say that when using the "unique" function on a timetable, it will take into account the row times and row values independently. However, when I use this function, it returns the exact same datatable even though there are hundreds of duplicate times. I used dateshift to round off the times to the nearest second but this didn't help. In my code, "Date_time" is the name of the first column of the table which contains the datetime values.
RadarTable = readtable('RADAR_DATA.xlsx');
RadarTable.Date_time = dateshift(RadarTable.Date_time,'start','second','nearest');
RadarTimeTable = table2timetable(RadarTable);
RadarTableFiltered = unique(RadarTimeTable);

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回答（1 个）

David Hill
David Hill 2022-2-23
RadarTable = readtable('RADAR_DATA.xlsx');
RadarTimeTable = table2timetable(RadarTable);
[~,idx]=unique(RadarTimeTable.time);%not sure what your time column is called.
RadarTimeTable=RadarTimeTable(idx,:);
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David Hill
David Hill 2022-2-23
If the answer is acceptable, please accept it to close out your question.
Kevin Johnson
Kevin Johnson 2022-4-19
%David, I have a similar problem and this did not work for me.
%The original timetable looks like this:
%tt=
19-Apr-2022 11:50:00 6.9388 6.9402 6.9354 6.9364 12.308 NaN
19-Apr-2022 12:00:00 6.9365 6.9373 6.9346 6.9361 12.299 NaN
19-Apr-2022 12:10:00 6.9361 6.9368 6.9344 6.935 11.226 NaN
% Let's say for some reason I download the same data again into ttagain and
% concatenate it with the original data, then attempt to remove the duplicates
% as follows:
tt=[tt;ttagain];
[~,idx]=unique(tt);
newtt=tt(idx,:);
%the results look like this:
%newtt=
19-Apr-2022 11:50:00 6.9388 6.9402 6.9354 6.9364 12.308 NaN
19-Apr-2022 11:50:00 6.9388 6.9402 6.9354 6.9364 12.308 NaN
19-Apr-2022 12:00:00 6.9365 6.9373 6.9346 6.9361 12.299 NaN
19-Apr-2022 12:00:00 6.9365 6.9373 6.9346 6.9361 12.299 NaN
19-Apr-2022 12:10:00 6.9361 6.9368 6.9329 6.9338 11.966 NaN
19-Apr-2022 12:10:00 6.9361 6.9368 6.9329 6.9338 11.966 NaN
%Duplicate rows are not eliminated. Why? What alternate approach might I use?
%Thanks,
%Kevin

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