Counting the number of binary toggles

Hello,

Say I have a binary array B of size n.

example arrays:

B_1 = [1 1 1 0 0 1 0 1 0 0 1];
B_2 = [1 1 1 1 0 0 0];

I am trying to think up an algorithm that would yield the number of switches(toggles) between 1 to 0 and conversely, 0 to 1.

For instance, with my binary array examples, I would like the result to be '6' for B_1 and '1' for B_2.

This is the code I devised, which entails linearly shifting the original array by 1 position and XOR'ing the shifted array with the original one, thus yielding the number of toggles. My problem is that it only works for certain arrays like B_1, yielding 6. But for arrays like B_2 the result is, erroneously 2:

B = [1 0 1 1 0 0 0 1 1];

B_shifted = circshift(B,1);

toggleArray = xor(B, B_shifted);

toggleCount = length(toggleArray(toggleArray==1)); %this is where I would like to store the desired result

Now I understand the limitations of my code, but I wanted to know if there was a more obvious, simpler, more elegant way that I am missing, or if there is a Matlab function that would do this for me.

Thanks!

Karam

Answer 1

[Walter Roberson]

nnz(diff(B_1))

[Karam Elabd]

lol nice, thanks Walt!