# How to save output from the for loop in a matrixs?

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Kabit Kishore on 24 Mar 2021
Commented: Kabit Kishore on 25 Mar 2021
Hi i have a matrix with M x n dimension. I have performed the peak analysis for each column in the for loop. I want to save the output for the for loop as a matrix.
I have used the following for loop.
for i=x
[pks,locs]=findpeaks((i),'MinPeakHeight',Thresold)
end
I get output like this :
##### 2 CommentsShowHide 1 older comment
Kabit Kishore on 24 Mar 2021
X is the matrix of M x n

Image Analyst on 24 Mar 2021
You can't pass (i) into findpeaks() - that's just a loop iterator, not a signal. You need to extract the column from your matrix. Then, since each column is not guaranteed to have the same number of peaks, you'll need a cell array to store the results.
[rows, columns] = size(data) % Size of your 2-D matrix of signals.
allPeakValues = cell(1, columns);
allPeakIndexes = cell(1, columns);
for col = 1 : columns
% Extract one column from the matrix.
thisColumn = data(:, col);
% Find the peaks in that column.
[thesePeakValues, theseIndexesOfPeaks] = findpeaks(thisColumn, 'MinPeakHeight', Threshold);
% Save the peaks for this particular column in our cell array that
% holds results for all the columns.
allPeakValues{col} = thesePeakValues;
allPeakIndexes{col} = theseIndexesOfPeaks;
end
Kabit Kishore on 25 Mar 2021
Thank you. It works perfectly

KALYAN ACHARJYA on 24 Mar 2021
Use Cell array to save the Matrices result
pks_data=cell(1,length(x));
locs_data=cell(1,length(x));
for i=1:x
[pks,locs]=findpeaks((i),'MinPeakHeight',Thresold);
pks_data{i}=pks;
locs_data{i}=locs;
end
Kabit Kishore on 24 Mar 2021
Thank you, However it give error as shown below

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