How to select rows in a matrix based on the values in another matrix?

Hi,

I have a matrix A and a matrix B:

-------- A -------              ---------- B ---------
201918      4.5                 201908     7     2.1
201917      4.1                 201918     8     0.3
201821     -7.1                 201917     9     0.1
201718      0.2                 201916     9     2
                                201903     6     18.1
                                201718     0     1.9

I need to intersect their first columns in order to find matching values within B, thus obtaining a matrix C:

---------- C --------     
201918     8     0.3
201917     9     0.1
201718     0     1.9

By using the function intersect(A(:,1), B(:,1)) I get the first column of C but how do I get the corresponding values of the other rows in B?

Answer 1

[David Hill]

C=B(ismember(B(:,1),A(:,1)),:);

Answer 2

[Jonas]

use

[~,ia,ib])=intersect(A(:,1), B(:,1));
A(ia,:)
B(ib,:)