Create columns with no zero sequentially elements of a vector
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I have a vector A=[4,2 3 2 2 0 0 1 2 2 0 0 1 2 3] and I am trying to create columns in new matrix with no zero sequentially elements, with a loop without success.Β1=[4,2 3 2 2] B2=[1 2 2] etc
I want to have a column with elements of A and when I find zero to create another column. Do you believe that it is feasible?
1 Comment
John D'Errico
on 28 Apr 2015
You do realize that matrices MUST be rectangular? So all columns of a matrix must be the same length. This is why you failed to produce a result, since your result would not have that property.
Accepted Answer
Image Analyst
on 27 Apr 2015
Edited: Image Analyst
on 27 Apr 2015
This is very easy with the Image Processing Toolbox. Simply use bwlabel() (and regionprops() if you're going to have some unknown number of regions rather than exactly 3).
A=[4 2 3 2 2 0 0 1 2 2 0 0 1 2 3]
labeled = bwlabel(A)
B1 = A(labeled==1)
B2 = A(labeled==2)
B3 = A(labeled==3)
Do you have that toolbox?
9 Comments
Image Analyst
on 28 Apr 2015
For regionprops() to get the values of the original array, you need to supply it.
A=[4 2 3 2 2 0 0 1 2 2 0 0 1 2 3];
[labeled, numRegions] = bwlabel(A);
measurements = regionprops(labeled, A, 'PixelValues');
for k = 1 : numRegions
B{k} = measurements(k).PixelValues
end
See my Image Segmentation Tutorial for a more comprehensive and well commmented demo. http://www.mathworks.com/matlabcentral/fileexchange/25157-image-segmentation-tutorial
More Answers (1)
Andrei Bobrov
on 27 Apr 2015
Edited: Andrei Bobrov
on 27 Apr 2015
B = zeros(size(A));
t = A > 0;
B(strfind(0,t],[0,1])) = 1;
b0 = cumsum(B);
Bout = accumarray(b0(t)',A(t)',[],@(x){x'});
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