How to check elements with value of 1’s in adjoining rows

Question

Vishal Sharma 2017-2-20

回答： Guillaume 2017-2-20

A = [1 1 0 0; 
1 1 0;
1 1 0; 
0 1 1; 
0 1 1]

How to check the result of 1’s in adjoining rows are equal.

i.e. 2nd element in 1st and 2nd row have common 1

2nd and 3rd elements in 2nd and 3rd row have common 1’s

3rd elements in 3rd and 4th row have common 1

3rd and 4th elements in 4th and 5th row have common 1

Answer 1

Guillaume 2017-2-20

~diff(A) & A(1:end-1, :)

will show you which element of each row is identical to the one in the next row. You can transform that into a cell array of indices with:

[r, c] = find(~diff(A) & A(1:end-1, :));
accumarray(r, c, [], @(x) {x})