How can I change zeros matrix to 1 by specific points??

9 views (last 30 days)
I have 8X8 Zeros matrix :
A = zeros(8, 8);
I need to create a multiple rectangles of Ones matrix. when I have specific points location:
first rectangular startfrom point [1,1] which are (X0, Y0) to [3,3] which are (X1, Y2).
and
second rectangular start from point [5,5] which are (X0, Y0) to [8,8] which are (X1, Y2).
I have try this but does not work with me:
%%first rectangular
A(([1,1]:[3,1]):([3,1]:[3,3]))= 1
%%second rectangular
A(([5,5]:[8,5]):([8,5]:[8,8]))= 1
Could you please help me.

Accepted Answer

Adam Danz
Adam Danz on 27 Nov 2019
Edited: Adam Danz on 27 Nov 2019
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.

More Answers (1)

Andrei Bobrov
Andrei Bobrov on 27 Nov 2019
A = zeros(8, 8);
A(1:3,1:3) = 1;
A(5:8,5:8) = 1;

Categories

Find more on Creating and Concatenating Matrices in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!