MATLAB: Creating a new matrix without certain rows with elements below a certain value

for loopgreater thaninequalitiesloopMATLABmatrix

I want to create a new matrix which is has the same values as my original matrix, M, minus those rows whose first column values are less than 3.

Does anyone know how I could correct my code to do this?

M=set7;

Mm=table2array(M);

N=Mm(Mm(:,1)>=3)

for (Mm(1:end,1)>=3)

B=Mm(:,2)

end

Nn=zeros(size(B,2))

Nn=(N,B);

Thanks!

Best Answer

If I'm understanding correctly, I believe your third line is enough (with the addition of a colon in the second subscript of M to avoid linear indexing):

idx = M(:,1) >= 3; % indices of rows to keep
N = M(idx,:);

Related Solutions

MATLAB: Eliminating Matrix Elements Which Exceeds Some Threshold with Using idx

A is a Matrix of m rows by n columns, therefore, idx is going to be a logical vector of m rows by 1 column, if any element in the row of A is less than -M / 2 or greater than M / 2 then in that row the idx value will be 1 otherwise it will be 0.

in out those rows of A that were positive in idx are going to be saved and from those rows we want to get all the columns, and after that in those same rows that were 1 with A (idx,:) = []; what is done is to eliminate them and have a new Matrix of A without those rows.

MATLAB: For loop, exceeded dimension error.

Simply run the loop backwards so row 4 doesn't become row 3 when row 3 is deleted.

e.g:

for jj = N:-1:i3
  %delete stuff
end

Now of course you're still best off (for speed) building an index vector and doing the whole delete once at the end.

idx = false(N-i3,1);
for jj = i3:N
 if stuff
    idx(jj) = true;
 end
 Mat(idx,:) = [];
end

Best Answer

Related Solutions

MATLAB: Eliminating Matrix Elements Which Exceeds Some Threshold with Using idx

MATLAB: For loop, exceeded dimension error.

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