MATLAB: How to flip values greater than zero in a row

flip

If I have a row in matrix like that

0 0 0 0 1 2 3 0 0 0

I want to make it like that

0 0 0 0 0 0 3 2 1 0

If it is possible to do?

Best Answer

Try this:

A=[0 0 0 0 1 2 3 0 0 0]
idx=find(A~=0);
A(idx+nnz(A)-1)=fliplr(A(idx));
A(idx(1:end-1))=0

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MATLAB: How to compare two cells which consist of the same values, and write the row number of the first to the other file

You actually don't need to run the comparisons. The unique function provides for this directly. So just modify the second line of your code as follows:

[Nodes_Unique,~,idx] = unique(Nodes,'rows');

And you can include the fourth column in AllCell as follows:

idx=idx-1; % seeing as you prefer to start with 0.
idx = num2cell(idx); 
AllCell = [AllCell,idx];

MATLAB: Txt file to matlab matrix form

Try this. Firstly read the file into a string (note that I removed the space at the end of the filename):

str = fileread('STIFFNESS MATRIX.txt');

Then extract the data from the block headers, including the row numbers:

[tok,idx] = regexp(str, 'ROW\s+(\d+)\s+NODE\s+(\d+)\s+[^\n=]+=\s+(\w+)', 'tokens', 'end');
tok = vertcat(tok{:});
idx = [1+idx,numel(str)];

Extract the data from the blocks:

fun = @(b,e)reshape(sscanf(str(b:e),'%f'),2,[]).';
mat = arrayfun(fun, idx(1:end-1), idx(2:end), 'UniformOutput',false);

Convert the data from string into numeric:

fun = @(r,v)[sscanf(r,'%i')*ones(size(v,1),1),v];
mat = cellfun(fun, tok(:,1), mat(:), 'UniformOutput',false);
mat = vertcat(mat{:});

And finally transfer the numeric data into one single numeric array, by using the row and column indices to allocate the data:

out = zeros(size(tok,1));
ind = sub2ind(size(out),mat(:,1),mat(:,2));
out(ind) = mat(:,3)

This gives one matrix containing the complete data:

>> out
out =
 1.0e+09 *
Columns 1 through 14
  0.1351  0  0.0915   -0.0591  0  0  0   -0.3660  0  0  0 ...
Columns 15 through 18
       0         0         0         0
       0         0         0         0
...
       0         0         0         0
       0         0         0         0
  1.4636   -0.0000         0         0
 -0.0000    0.0138    0.0001         0
       0    0.0001    0.5012         0
       0         0         0    0.5180

Best Answer

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MATLAB: How to compare two cells which consist of the same values, and write the row number of the first to the other file

MATLAB: Txt file to matlab matrix form

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