How fix Cell contents reference from a non-cell array object?

i have cell "checked_min_max" , i want to use each cell value in creating another matrix for each loop "new_ImgAsTxt" to perform calculations on then remove it the error "Cell contents reference from a non-cell array object" appears as i the matrix is empty. How could i solve it?

for vec_len = 1:size(checked_min_max, 1)
    st(vec_len, 1) = checked_min_max{vec_len, 1}(1)
    nd(vec_len, 1) = checked_min_max{vec_len, 1}(2)
    %
    new_ImgAsTxt(u, :) = cent_TxtAsImg(find(cent_TxtAsImg(:, 6) == st(vec_len, 1)), 1:4);
    new_ImgAsTxt(u + 1, :) = cent_TxtAsImg(find(cent_TxtAsImg(:, 6) == nd(vec_len, 1)), 1:4);
    minx = min(new_ImgAsTxt(u:u + 1, 1));
    miny = min(new_ImgAsTxt(u:u + 1, 2));
    max_x = max(new_ImgAsTxt(u:u + 1, 3));
    max_y = max(new_ImgAsTxt(u:u + 1, 4));
    W = max_x - minx;
    H = max_y - miny;
    new_ImgAsTxt = [];
    u = 1;
    minx = 1;
    miny = 1;
    max_x = 1;
    max_y = 1;
    checked_min_max = [];
end

Answer 1

[Stephen23]

The problem is this:

for vec_len = 1:size(checked_min_max, 1)
    ...
    checked_min_max = [];
end

Although before the loop it might be a cell array, at the end of the first loop iteration you define checked_min_max to be an empty numeric array. On the second loop iteration you try to access an empty numeric array as if it were a cell array.

Solution: You do NOT need to remove any cells in the loop for your code to work, so just remove the line of code where you redefine checked_min_max. In general it is a bad idea anyway to remove array elements like this in a loop, because it forces MATLAB to move the entire array to new memory on each loop iteration.