Counting number of matrix elements with 1 and 2.

Example of my matrix:

A = [10 1;

10 2;

11 1;

11 1;

12 1;

12 1;

12 2;

13 1;

13 1];

The first column is the id code and the second is the details. For example, id 10 has both 1 and 2, so it is counted. Id 11 has only 1s, so it is not counted. Id 12 has both 1 and 2 so it is to be counted. Based on the matrix above, my count shoould be 2. Is there a funtion wherein i can use to count the number of elements with 1 and 2 in a matrix? Or i need to use loop?

Answer 1

[Sajjad Asefi]

Hi there,

I think you can use the following method to get your answer without writting a "for" loop;

intersect(A(A(:,2)==1,1),A(A(:,2)==2,1))

All the best,

Sajjad

[AJA]

Thanks for this!