How to label the adjacent same value in a matrix

Hi,

Let's say I have a matrix like below:

A = [2 3 4 5 1 1 2 3 1 1 1 1;
     8 5 1 1 1 1 5 4 1 0 1 1;
     5 1 1 1 3 1 1 1 5 5 5 1;
     1 1 1 2 1 1 2 1 1 1 6 8;
     0 1 1 3 3 1 1 5 7 6 1 1]

I would like to know if there is any way to group and label every element if the adjacent(top, down, left, and right) value are equal to a specific value. For example, I want to group and label if the elements are equal to 1 in A. Thus, there are three groups, one of which is the largest on the left (24 elements), the second one is on the top-right corner (8 elements), and the third is on the bottom-right corner (only 2 elements). The result I expected is 3 groups with how many elements they have. Thanks in advance.

Answer 1

[Walter Roberson]

bwlabel(A==1,4)

[ccbarrylee]

Thanks! It's exactly what I want!