How to count the number of 1 between two 0 in a vector?

I have this vector:

[0 1 1 1 0 0 1 0 1 1 0 1]

I want to create a vector that every time that I have 1 or more consecutive 1 it counts the number of 1 between two zero. So the results must be:

[3 1 2 1]

How can I do that?

thanks

Answer 1

[Adam Danz]

In both methods below,

A is the input vector (row or column)

B is the output vector of consecutive 1 counts, row vector.

Method 1 assumes the vector only contains 1s and 0s

A = [0 1 1 1 0 0 1 0 1 1 0 1];
B = diff(find([0,A(:).',0]==0))-1; 
B(B==0) = []

B = 1×4

3 1 2 1

Method 2 counts consecutive 1s, other elements can take any numeric value.

A = [0 1 1 1 0 0 1 0 1 1 0 1];
dA = diff([0,A(:).',0]==1);
B = find(dA==-1)-find(dA==1)

B = 1×4

3 1 2 1

Answer 2

[Sean de Wolski]

[regionprops(bwlabel([0 1 1 1 0 0 1 0 1 1 0 1]),'Area').Area]

[Adam Danz]

I was also thinking about using bwlabel for those who have the Image Processing Toolbox.

A = [0 1 1 1 0 0 1 0 1 1 0 1]; 
B = histcounts(bwlabel([0,A(:).',0]),'BinMethod','integer'); 
B(1) = []; 

[Sean de Wolski]

A vector is just a long and skinny image! I find things like bwlabel, bwareaopen, etc. to often be useful for this kind of thing.

[Adam Danz]

Agreed - I'm relatively new to the bw.... functions but I use bwlabel often. Since it requires access to a toolbox I went with a lower level solution in my answer.