Counting the number of elements that match between a vector and a matrix

I'm looking to count the number of elements that match between a vector and a matrix. I've used the code below:

K= magic(10);
vec=[0 3 7 9 11];
for i= 1:length(vec),
  sum(sum(K==vec(i))),
end

This keeps giving me a string of "ans=1" values, rather than the total number of elements that match up (It should be 4 that match). What can I change?

Answer 1

[Andrei Bobrov]

nnz(ismember(K,vec))

[Andrei Bobrov]

comment by Natalie Culhane (copy):

Perfect, thank you. Is there an alternative to using nnz?

[Andrei Bobrov]

Hi Natalie!

variant without nnz :

sum(ismember(K(:),vec)) % corrected after comment by Azzi

[Azzi Abdelmalek]

idx=ismember(K,vec)
out=sum(idx(:))