How to find index in cell array to start cumsum

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Jonathan Cheong 2021-3-7

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https://ww2.mathworks.cn/matlabcentral/answers/765091-how-to-find-index-in-cell-array-to-start-cumsum

编辑： Jonathan Cheong 2021-3-8

采纳的回答： Jonathan Cheong

ddvaluecell.mat

Hello, I have a cell array 'ddvaluecell'.

I would like to find the index of values in these cells which are > 0.5.

Then starts a cumsum for the next 5 indices or stop early when it reaches 3.

How do I do this?

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Walter Roberson 2021-3-7

Also take the time to decide what you want to do if there are multiple nearby values that meet the test. Do you want to process separately for each possible starting point Do you want to bundle all of the values within a window of 5 together only making one start for the window? Even if the sum ends early? Do you want to bundle all consecutive >½ together but only take starting from the first of the group?

Jonathan Cheong 2021-3-7

Thanks for the suggestion, I'll give it a go

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Jonathan Cheong 2021-3-8

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https://ww2.mathworks.cn/matlabcentral/answers/765091-how-to-find-index-in-cell-array-to-start-cumsum#answer_641581

编辑：Jonathan Cheong 2021-3-8

在 MATLAB Online 中打开

Ok, so this is the answer.

% Index of starting cumsum
indices = cellfun(@(C) find(C>0.5), ddvaluecell, 'uniform', 0);
indexes = cellfun(@(x,ii) x(ii),ddindexcell,indices, 'uniform', 0);
% Change cell into array
indexarray = padcat(indexes{:}); % Pad rows with PADCAT function 
indexarr = indexarray(:).'; % Change into column form
indexarr = indexarr(~isnan(indexarr)); % Remove all NaN 
sumsum = zeros(0,size(rain,2));
indsum = [];
indend = [];
 for bi = indexarr % Iterate over start indices (1x140)
    cs = cumsum(rain(bi:end));
    csp = find(cs <= 2.5); % Stop when reach 2.5mm    
    if numel(csp) <= 5 % Cumsum less than 5 days is used
    inds3_5 = bi-1 + csp;
    sumsum = [sumsum;rain(inds3_5,:)]; % append data
    indsum = [indsum; inds3_5]; % append indices
    ddearly = [indsum, sumsum]; % Index and value side by side     
    indend = [indend; inds3_5(end)];  % Last index of cumsum
    end
 end