Find out the cell index from matric values

Hi all,

I want to find out the cell index of each row of matrix A. Each row has two values that correspond to x and y. I need to construct an index matrix that has the cell indeicies of each row depening on the x and y values. The below example hopefully clarifies the idea:

Here is my code attempt:

for i = 1:size(A,1)
    for n = 1:numel(x)
        for m = 1:numel(y)
            %check the limits of each cell
            if (A(i,1) <= x(n)+dx || A(i,1) >= x(n)) && ...
                    (A(i,2) <= y(m)+dy || A(i,2) >= y(m))
                %find out the cell index
                %Here where I need help!
            end
        end
    end
end

Thanks.

Answer 1

[Akira Agata]

How about using histcount2 ?

The following is an example:

% Sample data
A = [...
  0.7, 0.1;...
  0.1, 0.2;...
  0.8, 0.6;...
  0.3, 0.7];

% Edge for histcount2
edge = [0, 0.5, 1];

% Find x-bin and y-bin IDs for each data point
[~, ~, ~, binx, biny] =...
  histcounts2(A(:,1), A(:,2), edge, edge);

% Convert x-bin and y-bin IDs to cell ID
cellID = biny + 2*(binx-1);

% Display the result
disp(cellID)

     3
     1
     4
     2

[Lama Hamadeh]

Thanks. Would that work if x and y are split differently? Instead of having an grid, we have ?

[Akira Agata]

Yes, of course! You can do that task by setting different edges for x- and y-axes, like:

% Edge for histcount2
edge_x = 0:0.5:1;
edge_y = 0:0.2:1;

% Find x-bin and y-bin IDs for each data point
[~, ~, ~, binx, biny] =...
  histcounts2(A(:,1), A(:,2), edge_x, edge_y);