How to make unique vector with probability of elements?

I have a matrix A= [22 1;24 0; 23 1; 24 1; 22 1]. I want to drive a new matrix like below: B= [22 1;23 1;24 0.5] in which the first column is the "unique" of A and the second column is the probability of these elements. That means the every of second column elements of similar first columns in A: - in A there are two rows with 22 and both of them have probability of 1, that means in B 22 has probability of 1 - But for 24 there is two different 0 and 1. So in B it must be 0.5.

Answer 1

[Matt J]

B=splitapply(@(z)mean(z,1), A, findgroups(A(:,1)))

[sia ben]

Thanks it works well1!