MATLAB: Extract group of identical values from an array

Question

I have the array

a = [0 0 0 1 1 1 0 0 0 0 0 1 1 1 1 0 0 1 1];

I want to extract the first and last index where a==1 as a group

o/p: [4 6; 12 15; 18 19];

Is there any efficient way to do this?

Answer 1

If you have the image-processing toolbox.

bwconncomp()