How can I join columns of an array without overlapping elements?

Question

Emanoel Santos 2022-9-20

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1808240-how-can-i-join-columns-of-an-array-without-overlapping-elements

评论： Emanoel Santos 2022-9-20

So, I have a tri-diagonal (10x10) and would like to join some columns without overlapping the elements, that means columns 1,4, 7 and 10 can be joined without overlapping as well columns 2,5,8. All I have to do is put this elements together and all the other elements turn to 0. This is what I get, any suggestion? X is a random tri-diagonal matrix and Y the matrix with the joined columns.

clear all
x = [1 1 0 0 0 0 0 0 0 0; 2 3 4 0 0 0 0 0 0 0; 0 1 1 1 0 0 0 0 0 0; 0 0 1 1 1 0 0 0 0 0; ...
    0 0 0 1 1 1 0 0 0 0; 0 0 0 0 2 4 3 0 0 0; 0 0 0 0 0 4 5 1 0 0; 0 0 0 0 0 0 1 1 1 0; ...
    0 0 0 0 0 0 0 1 1 1; 0 0 0 0 0 0 0 0 1 1];
[nelem,ielem] = size (x);
y=zeros(nelem,nelem);
lin = 1;
col = 1;
j = 2;
if (x(lin,col) == 0 && x(lin,j) ~= 0 || (x(lin,col) ~= 0 && x(lin,j) == 0) || (x(lin,col)) == (x(lin,j)))
    if(x(lin,col))~=0
        y(lin,col)=x(lin,col);
        
    elseif (x(lin,j))~=0
        y(lin,col)= x(lin,j);
    else
        y(lin,col)=x(lin,col);
    end
end
%COLUNAS 1 e 2
% for i = 2:nelem
i = 2;
while (i < nelem && j < nelem)
    while (((x(i,col)==0)&&(x(i,j)~= 0))||((x(i,col)~=0)&&(x(i,j)==0))||((x(i,col)==0)&&(x(i,j)==0))&&j<nelem)
        if (x(i,col)) ~= 0
            y(i,col) = x(i,col);
        else
            y(i,col) = x(i,j);
        end
        if (i<nelem)
            i=i+1;
        elseif (i == nelem)
            i = 1;
            col = col +1;
            j = j+1;
        end
    end
    if (i < nelem && j < nelem)
        y(:,col) = x(:,col);
        i = 1;
        j = j+1;
    end
end
while(((x(i,col)) == 0 && (x(i,j)) ~= 0 || (x(i,col)) ~= 0 && (x(i,j)) == 0 ||(x(i,col)) == (x(i,j))) && i<nelem)
    if (x(i,col) ==(x(i,j)))
        y(i,col) = (x(i,col));
    end
    if((x(i,col))~=0 && (x(i,j)) == 0)
        y(i,col)=x(i,col);            
    elseif ((x(i,col))==0 && (x(i,j)) ~= 0)
        y(i,col)=x(i,j);
    end
    i=i+1;
end
if (x(i,col) ==(x(i,j)))
    y(i,col) = (x(i,col));
end
if((x(i,col))~=0 && (x(i,j)) == 0)
    y(i,col)=x(i,col);            
elseif ((x(i,col))==0 && (x(i,j)) ~= 0)
    y(i,col)=x(i,j);
end

6 个评论
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Emanoel Santos 2022-9-20

for example, the columns bellow:

Chunru 2022-9-20

See the updated answer.

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Answer 1

Chunru 2022-9-20

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1808240-how-can-i-join-columns-of-an-array-without-overlapping-elements#answer_1056800

编辑：Chunru 2022-9-20

在 MATLAB Online 中打开

Not sure if this is what you intend to do:

x = [1 1 0 0 0 0 0 0 0 0; 
3 4 0 0 0 0 0 0 0;
1 1 1 0 0 0 0 0 0; 
0 1 1 1 0 0 0 0 0;
0 0 1 1 1 0 0 0 0; 
0 0 0 2 4 3 0 0 0; 
0 0 0 0 4 5 1 0 0; 
0 0 0 0 0 1 1 1 0;
0 0 0 0 0 0 1 1 1; 
0 0 0 0 0 0 0 1 1];
y = zeros(size(x));
y(:, 1) = sum(x(:, [1 4 7 10]), 2);
y(:, 2) = sum(x(:, [2 5 8]), 2);
y(:, 3) = sum(x(:, [3 6 9]), 2);
y
y = 10×10
   1     0     0     0     0     0     0     0     0
   3     4     0     0     0     0     0     0     0
   1     1     0     0     0     0     0     0     0
   1     1     0     0     0     0     0     0     0
   1     1     0     0     0     0     0     0     0
   2     4     0     0     0     0     0     0     0
   1     4     0     0     0     0     0     0     0
   1     1     0     0     0     0     0     0     0
   1     1     0     0     0     0     0     0     0
   0     1     0     0     0     0     0     0     0