Check if (x,y) point is within 2d array of (x,y) entries. Where x is one column and y another

Is there a way to check if (x,y) points is within 2d array of (x,y) entries. Where x is one column and y another. Preferably I want a list of boolean variables with 1 if (x,y) point is present in that positon and zero otherwise

[Sathya Sri Chikoti]

Matlab function ismember can be used for this purpose. You could try the code below:

x = 3;
y = 7;
a=[1 2 3 4; 5 6 7 8];
isPresent = any(ismember(a.', [x y], 'rows'));

Answer 1

[Rishabh Mishra]

Hi,

I would like to point out that to create a matrix of points (x,y) you can use complex number. For example, consider the matrix defined below:

mat = [1+2i 3+i; 
        3+4i 1+2i]; 

The above matrix is used to store the cartesian pairs (1,2), (3,1), (3,4) and (1,2).

Let’s say you want check if point 1+2i is present in the matrix or not. You can use the code below:

mat = [1+2i 3+i; 
        3+4i 1+2i]; 
  
point = 1+2i; 
check = [mat == point]; 

Check is Boolean matrix that lists out the positions in original matrix where the point 1+2i is present.

Feel free to revert for any clarifications or queries.

Hope this helps.

[Jacqueline Chernen]

Can you explain why you used imaginary numbers?