Count size of groups of 1's

Hi all, this is my first question on the forum.

I have a vector called gpos that have 1's where I have a NaN value (gpos = isnan(data);)

For example

gpos = [1 1 1 0 0 1 1 0 1 1]'

I'd like to count the size of groups of 1's, like my expected result. How do I accomplish that? Thanks in advance.

result = [3 2 2]'   % ignoring data that is zero

Answer 1

[Erivelton Gualter]

Here is a way you can perform this:

gpos = [1 1 1 0 0 1 1 0 1 1]';

[I, ~] = find(gpos == 1);

k = 0;
result = [];
for i=2:length(I)
    if (I(i)-I(i-1)) ~= 1
        result = [result; k+1];
        k = 0;
    else
        k = k + 1;
    end
end
result = [result; k+1];

disp(result);

But definetly, you might write something simpler .

[Matt J]

David AR's comment moved here:

Thank you. The code works flawlessly. Best regards.

Answer 2

[Pablo Rozier-Delgado]

Another way, without for loop:

gpos = [1 1 1 0 0 1 1 0 1 1]';          % Detected NaNs
indGroups = bwlabel(gpos) + 1;          % Label groups of ones and make it positive integers
result = accumarray(indGroups,gpos);    % sum of each groups
result(result == 0) = []                % delete the 0 group

result = 3×1

3 2 2