how to remove zeros from the matrix?

Hello, I want to remove zero values from the matrix and cut the last elements of odd rows. For example, if I have a matrix

A=[1, 0, 2, 0, 3 ;

0, 4, 0, 5, 0 ;

6, 0, 7, 0, 8]

and, I want to make matrix like

B=[1, 2;

4, 5;

6, 7]

Please answer this question. Thanks!

[Turlough Hughes]

Do you always get n or n+1 zeros in a given row, and what do you mean by odd low?

[Junseob Kim]

Sorry, I mean odd rows.

[Junseob Kim]

And yes. If I have n zeros in odd rows, there are n+1 zeros in even rows.

[James Tursa]

Is it always the checkerboard pattern shown?

[Junseob Kim]

Yes it is.

Answer 1

[the cyclist]

I think this does what you want:

% Replicate A into B
B = A;

% For the even-numbered rows, circularly shift the elements
B(2:2:end,:) = circshift(B(2:2:end,:),-1,2);

% Remove any columnn with a zero
B(:,any(B==0)) = [];

[Junseob Kim]

Thank you so much!!

Answer 2

[Guillaume]

A=[1, 0, 2, 0, 3 ; 
   0, 4, 0, 5, 0 ; 
   6, 0, 7, 0, 8];

B = reshape(nonzeros(A(:, 1:end-1).'), [], size(A, 1)).'

[Junseob Kim]

Thank you so much!!

Answer 3

[Adam Danz]

This approach extracts the first two non-zero elements per row. If there are no two non-zero elements in each row an error is thrown.

A=[
    1, 0, 2, 0, 3 ;
    0, 4, 0, 5, 0 ;
    6, 0, 7, 0, 8];

B=[1, 2;
    4, 5;
    6, 7];

% Number of non-zeros per row or A
numNonZeros = sum(A~=0,2); 

% Replace the non-zeros after the 2nd non-zero in
% each row with 0s
A(cumsum(A~=0,2) > 2) = 0; 

% Confirm that we end up with 2 non-0s in each row
if (unique(sum(A~=0,2))>0) ~= true
    error('Assumption violation: the number of non-zeros in each row of A is unexpected.')
end

A = A.'; 
B = reshape(A(A~=0),2,size(A,2)).'; 

[Junseob Kim]

Thank you so much!!

Answer 4

[Kaspar Bachmann]

A=[1, 0, 2, 0, 3 ; 0, 4, 0, 5, 0 ; 6, 0, 7, 0, 8]

Var = A;

Var(:,length(Var)) = [];

for i = 1:size(Var,1)

t = Var(i,:);

idx = find(t>0);

B(i,:) = t(idx);

end

Its a bit messy, but it should work.

[Junseob Kim]

Thank you so much!!