select rows satisfying a particular condition

having a matrix of dim 5 x 10

if i give start_index = 1, and end_index = 3, i wanted to get rows starting with value of start_index and ending with end_index excluding zeros.

eg: rows 4 and 5

 cell_matrix = {[1  2  3] 
 [1  3] }

saved to a cell matrix

Answer 1

[Andrei Bobrov]

% Let A - your array.

[ii,jj,v] = find(A);
z = [ii,jj,v];
z = sortrows(z,[1,2]);
out = accumarray(z(:,1),z(:,3),[],@(x){fun(x,1,3)});

function out = fun(x,b,e)
    x = x(:)';
    out = [];
    if isequal(x([1,end]) , [b,e]) && all(diff(x(:)) > 0)
        out = x;
    end
end

Answer 2

[Alex Mcaulley]

a = randi([0,2],5,10);

start_index = 1;
end_index = 3;

b = mat2cell(a(start_index:end_index,:),ones(1,end_index-start_index+1),size(a,2));
b = cellfun(@(x) myfun(x),b,'UniformOutput',false);

function x = myfun(x)
    x(x==0) = [];
end