Summing few sequences in a vector

How can I sum few sequences in a vector? For example, if I have the vector:

A = [1 1 0 4 1 1 0 2 1 1 1]

I want to get the vector:

B = [2 6 5]

Which is the sum of sequences separated by zero.

Of curse I wand to do it without any for/while loops.

Thank you.

Answer 1

[Walter Roberson]

t1 = cumsum(A);
B = diff([0,t1(A==0),B(end)]);

[George Tsintsadze]

You can't execute the second line because B is not defined before it and you are using it in this line.

I tried your code and got the warning:

Undefined function or variable 'B'.

Do you have a suggestion how to fix it?

[Walter Roberson]

t1 = cumsum(A);
B = diff([0,t1(A==0),t1(end)]);

Answer 2

[KSSV]

A = [1 1 0 4 1 1 0 2 1 1 1] ;

ne0 = find(A~=0);                                   % Nonzero Elements
i0 = unique([ne0(1) ne0(diff([0 ne0])>1)]);        % Segment Start Indices
i1 = ne0([find(diff([0 ne0])>1)-1 length(ne0)]);   % Segment End Indices
for k1 = 1:length(i0)
    section{k1} = A(i0(k1):i1(k1));
end
iwant = cellfun(@sum,section)

[George Tsintsadze]

Sorry but I asked for solutions without any for/while loops...

Answer 3

[José-Luis]

Not particularly efficient but fulfilling the eternal quest for one liners:

 result = cellfun(@(x) sum(x((x - '0') > 0 & (x - '0') <= 9 ) - '0'), strsplit(num2str(A),'0'))

[George Tsintsadze]

Why did you add the condition

 (x - '0') <= 9

in the logical indexing of x?

[José-Luis]

Because

 strsplit(num2str(A),'0')

returns a cell array of character arrays and I wanted to perform the comparisons on numbers. It's just a way of transitioning from characters to numbers. Otherwise some unnecessary blank characters would have been included in the computation.

Please accept the answer that best solves your problem.