MATLAB: Weekly to six monthly sum

accumarraydatesMATLABmatrix sumnansum

Hi All

I have a matrix (named "X") with dimension 2196,7

Matlab (weekly) dates are in the first column and next 6 columns have prices

I wish to add (nansum) the first six month values and this becomes one observation in a new matrix "Y". Similarly, the sum of next six month values becomes the 2nd observation in matrix Y. And we do this till the last date (observation 2196).

Thanks for helping me in advance.

Regards

AHM.

Best Answer

   Y = reshape(nansum(reshape(X(:,2:7), [], 26, 6),2),[],6);

This will not have any date entries, but you did not define how you wanted that column handled. You could use

[X(1:26:end,1), Y]

if you wanted to select the first date of each group as indicating the time period.

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Let data - your array [978 x 744].

For MATLAB >= R2016b (here week -> [Sun : Sat]):

Time = (datetime([2017 7 1 0 0 0]):hours(1):datetime([2017 7 31 23 0 0]))';
% or: Time = datetime(timeCopy);
TT = array2timetable(data','R',Time);
TT_out = retime(TT,'weekly','mean');

For MATLAB < R2016b ( here week -> [Mon : Sun]):

data = data';
Time = (datetime([2017 7 1 0 0 0]):hours(1):datetime([2017 7 31 23 0 0]))';
wd = rem(weekday(Time) + 5, 7) + 1;
ii = [true;diff(wd == 1) == 1];
g = cumsum(ii);
[r,c] = ndgrid(g,1:size(TT,2));
TT_out = [table(Time(ii),'V',{'Time'}),...
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Use an appropriate function to read the file (readmatrix, or a similar appropriate function), then try this prototype code with your data:

Y = ones(31,1)*2021;                                            % Create Original Year Data
M = ones(31,1);                                                 % Create Original Month Data
D = (1:31).';                                                   % Create Original Day Data
Date = datetime([Y,M,D]);                                       % Convert To ‘datetime’
Temperature = 20 + 5*sin(2*pi*D/31)+randn(size(D))/10;          % Create ‘Temperature’ Vector
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TT1 = table2timetable(T1);                                      % Convert To ‘timetable’
TT2 = retime(TT1,'weekly','mean');                              % Timetable With Weekly Averages

Make appropriate changes to work with the available data.

Best Answer

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