MATLAB: Removing /eliminating bottom rows of a matrix

deleterows

I have a matrix imat=[1 1 1 1 1 1 1 0 1 1 1 1 0 0 0 1 1 0 1 0 0 0 1 0 0]; and a matrix imat= [0 0 1 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 1 0 0 0 1 1 1 0 0 0 0 0 0] I want 'mat' matrix as the size of 'imat' matrix. mat size is 8X8 and mat=5X5. I want to remove the three rows of mat matrix. Can anyone help please.

Best Answer

You named both matrices imat here. For 8x8 matrix named mat, for the first 5 columns and rows i.e. 5x5:

mat(1:5,1:5)

Related Solutions

MATLAB: How to remove certain rows and columns in a matrix

 w = A([1,2,7,8], :)
 Wanted = w(:, [1,2,7,8])

MATLAB: How to change zeros matrix to 1 by specific points?

Here's a demo. When [x0,y0] is [4,3] and [x1,y1] is [6,7], a rectangle of 1 will be placed in matrix A in rows 3:7 from the top and columns 4:6 from the left.

See inline comments for details.

% Create 0s matrix
A = zeros(8, 8);
% Define [x0,y0] and [x1,y1]
x0 = 4; 
y0 = 3; 
x1 = 6; % x1 >= x0
y1 = 7; % y1 >= y0
% replace section with 1s
[y,x] = meshgrid(x0:x1, y0:y1); 
idx = sub2ind(size(A),x,y); 
A(idx) = 1

Result

A =
     0     0     0     0     0     0     0     0
     0     0     0     0     0     0     0     0
     0     0     0     1     1     1     0     0
     0     0     0     1     1     1     0     0
     0     0     0     1     1     1     0     0
     0     0     0     1     1     1     0     0
     0     0     0     1     1     1     0     0
     0     0     0     0     0     0     0     0

If you'd rather use logicals, replace zeros() with false() and replace A(idx) = 1 with A(idx) = true.

Best Answer

Related Solutions

MATLAB: How to remove certain rows and columns in a matrix

MATLAB: How to change zeros matrix to 1 by specific points?

Related Question