MATLAB: How to count first identical elements without a for cycle

countvector

I have a vector [3 3 3 3 3 4 1 1 0 0 0 5 6 3 3 1 1 1], and I want to count threes at the begining of the vector, so the result has to be 5.

In case you want to measure the run length of the first run:

 data=[3 3 3 3 3 4 1 1 0 0 0 5 6 3 3 1 1 1];
 output=find(diff(data),1,'first');

And if you want to measure the run length of the first run of 3:

 
data=[5 3 3 3 3 3 4 1 1 0 0 0 5 6 3 3 1 1 1];
ind=find(data==3,1);
if ind>1
    data(1:(ind-1))=[];
end
output=find(diff(data),1,'first');

ix=([logical(0);(diff(A(1:N))~=0)]);
L(find(id))=A(id);
locais=L(2:end);

I've got a meeting...gotta' run for now, sorry...

Undoubtedly can vectorize remaining fairly much, too.

One thing is it doesn't appear the for k=1:j B(k)=locais(k)'; end B=B(:);

loop does anything that

B=locais;

doesn't other than perhaps the column/vector orientation. I'd say create B to begin with and fix the orientation there as wanted/needed...

% data
Y = [1 1 3 2 3 1 1 2]  % M = numel(Y)
K = 3
% engine
T = double((Y(:) - (1:K))==0)