Uninterrupted segment length?

Let's say I have an array indexes:

Indexes = [1122221122111211112222222]

How do I get the length of uninterrupted 2s? I want to output to be

output=[ 4 2 1 7]

Answer 1

[bio lim]

For a number that has longer digits, I am not sure. However, if it is within acceptable number of digits

format long
Indexes = [112222112211121];
newIndexes=str2double(regexp(num2str(Indexes),'\d','match'))
coffee = find(diff([-1 newIndexes -1]) ~= 0);
length = diff(coffee);
output = length(1+(newIndexes(1)==1):2:end);

The output is:

output =

       4     2     1

Answer 2

[Roger Stafford]

f = find(diff([false,Indexes==2,false])~=0);
output = f(2:2:length(f))-f(1:2:length(f));

[Qisq]

Very elegant solution. Thanks.