MATLAB: How to delete every nth row

delete

I have a given matrix and I would like to delete every nth row. (Is there any particularity I have to keep in mind given that my matrix will generally not be a multiple of n?)

Best Answer

If your matrix is A, then

A(n:n:end,:) = [];

will delete every nth row. Your matrix row count does not need to be evenly divisible by n.

Related Solutions

MATLAB: Finding average of every nth row

This is the mean over 6 subsequent rows:

x  = rand(9985, 1);
S  = numel(x);
xx = reshape(x(1:S - mod(S, 6)), 6, []);
y  = sum(xx, 1).' / 6;

The trailing rows are ignored.

[EDITED] General method for matrices:

x  = rand(9985, 14);
p  = 6;
n  = size(x, 1);          % Length of first dimension
nc = n - mod(n, p);       % Multiple of p
np = nc / p;              % Length of result
xx = reshape(x(1:nC, :), p, np, []); % [p x np x size(x,2)]
y  = sum(xx, 1) / p;      % Mean over 1st dim
y  = reshape(y, np, []);  % Remove leading dim of length 1

MATLAB: How to sum every nth row

 A = [1 2 3 4 5 6 7; 1 3 5 7 9 11 13; 2 4 6 8 10 12 14]';
 [n,col] = size(A);
 index = 1:n;
 elem = [repmat(3,1,floor(n/3))];
 endv = n-sum(elem);
 if(~endv)
     endv = [];
 end
 index = mat2cell(index,1,[elem,endv])';
 B = cell2mat(cellfun(@(x) sum(A(x,:),1),index,'un',0));
 B =
     6     9    12
    15    27    30
     7    13    14

Best Answer

Related Solutions

MATLAB: Finding average of every nth row

MATLAB: How to sum every nth row

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