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Extracting specific rows with different content from a large table array

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Carl Schneegaß
Carl Schneegaß on 28 Sep 2020 at 15:39
Answered: Steven Lord on 28 Sep 2020 at 15:53
I have several tables (a x 3; double, double, string).
The first double contains Matlab Dates, the 2nd contains numbers between 0 and 1.
I would like to extract the data of specific days, e.g. SpecificDay-30:SpecificDay+10
For example, I would like to extract all 41 rows where MatDate is (SpecificDay-30:SpecificDay+10) when SpecificDay = 736958 (which is datenum(2017,09,20)).
This is how one of the tables looks like:
Thank you so much in advance!

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Answers (4)

madhan ravi
madhan ravi on 28 Sep 2020 at 15:52
ix = find(TaBle.MatDate == 736958);
Wanted = TaBle{(ix-30):(ix+10), :}

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Turlough Hughes
Turlough Hughes on 28 Sep 2020 at 15:53
Tnew = T(T.MatDate>=SpecificDay-30 & T.MatDate<=SpecificDay+10,:);

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Steven Lord
Steven Lord on 28 Sep 2020 at 15:53
Consider storing your data in a timetable, converting your MatDate variable into a datetime array and using table2timetable (or manually creating a timetable from the variables.) If you do this you can use timerange to extract rows in a certain interval.
rng(999, 'twister') % Arbitrarily chosen to make the problem a little more interesting
% Create some sample data
N = datetime('now');
dt = N + minutes(randi([-180 180], 10, 1));
x = (1:10).';
% Build a timetable
T = timetable(dt, x)
% Make the timerange to use in indexing into T
thirtyToSixty = timerange(N+minutes(30), N+minutes(60))
% Index into T
T(thirtyToSixty, :)

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Sudheer Bhimireddy
Sudheer Bhimireddy on 28 Sep 2020 at 15:51
Convert the datenum to datetime, and then you can use the MATLAB function isbetween() to get all the indices that satisty your criteria.

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