MATLAB: How to run completely a loop inside one other

cell arraysfor loop

Hi! i have the data attached. ID_stop1 is an identifier of data and it is repeated 80 times for each value. Nn1 is a number from 1 to 20 and it is still repeated for each unique value of ID_stop1. Bn1 is a number from 1 to 20 and it is repeated for each unique value of Nn1. I need to access to data of L1 for each ID_stop1 and each Nn1. I created this code that works but at the end of the second loop it stops. How can i come back to the first loop?

I would like to have a cell array of 20 cells, and for each cell there should be 20 sub cells.

Any helps?

load ('sclerometrica_equotip_v1')
misure = [ID_stop L Nn Bn];
% misure(any(isnan(misure), 2), :) = [];
ID_stop1 = misure(:,1);
L1 = misure(:,2);
Nn1 = misure(:,3);
Bn1 = misure(:,4);
k = unique(ID_stop1);
for i = 1:numel(k)
    index = (ID_stop1 == k(i));
    N= Nn1(index); %battute nodi
    j = unique(N);
    for m = 1:numel(j) 
        index2 = (N == j(m));
        L_nodo = L1(index2);  
        result{m} = L_nodo;
    end
end

Best Answer

I suspect that the issue is not that the code actually stops, but that the results are only recorded for one internal loop. If you want cells inside of cells then you need to index for each loop.

results{i}{m} = L_nodo;

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MATLAB: How can i build a for loop to create histograms for a multiple cell array

First, don't use 2D indexing for vectors. result{ii} will work whether result is a row or column vector. Your result{1, ii} will only work for a row vector and fail if that untested assumption is broken.

Note that the output of result{ii} (or result{1, ii}) is, as you've stated a 1x20 cell array. Again, it's a vector and you're using 2D indexing on that with index (:, ii+1). Since that cell array has only 1 row, : is equivalent to 1, so your Lnodo1 is:

Lnodo1 = cell2mat(result{1, ii}(1, ii+1));

written a lot more simply as

Lnodo1 = result{ii}{ii+1}; %the use of cell2mat is pointless, {} indexing instead of () indexing yields the same result

So basically, you Lnodo1 is in turn result{1}{2}, result{2}{3}, ..., result{20}{21}. That last one will cause an index exceeds matrix dimension error as well. Certainly it doesn't do what you want but I'm not sure why you didn't spot that.

Since you want to interate over the cells of the outer array and the cells of the inner array, you need a double for loop

for outer = 1:numel(result)  %prefer numel to length, it's safer
    for inner = 1:numeL(result{outer})
        L_nodo1 = result{outer}{inner};
        %... your histogram code. Perfer histogram to hist
        pngfilename = sprintf('hist%d_%d.png', outer, inner);
        %... rest of export code
    end
end

As Image Analyst suggest, you could avoid the cell arrays entirely, and store your data as an 80x400 matrix, which would make your life simpler, would use a lot less memory and be faster to process.

MATLAB: How can i build a for loop for a subset of data having repetitions

Maybe you want:

k      = unique(IDstop1);
result = cell(1, numel(k));
for i = 1:numel(k)
    index = (IDstop1 == k(i));
    y  = Rmean_pred1(index);  
    x1 = Rmean_obs1(index);
    x2 = Zero1(index);
    X  = [ones(size(x1)), x1, x2];
    b  = regress(y, X);
    result{i} = b;
end

Best Answer

Related Solutions

MATLAB: How can i build a for loop to create histograms for a multiple cell array

MATLAB: How can i build a for loop for a subset of data having repetitions

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