How to count for how many duplicate elements exist in a vector and a matrix?

[Cornel]

Hello,

How to count for how many duplicate elements (excluding the original element) exist in a vector and a matrix?

So, as example if in t1 vector element 2 is present for four times, then element 2 has 3 duplicate (four times - 1 time for original element = 3 duplicate).

[Werner_E · Accepted solution]