How to create a limited frequent values in array?

Is there anyone know how to create limited frequent values in array? Because, what I found is only the most frequent. I'd like to make it like two or three times appear. For example this problem :

Return a list of all values (sorted smallest to largest) that appear exactly three times in the input vector x. So

if

x = [1 2 5 2 2 7 8 3 3 1 3 8 8 8]

then

y = [2 3]

Answer 1

[Wayne King]

You can use hist() and unique()

x = [1 2 5 2 2 7 8 3 3 1 3 8 8 8];
[N,bins] = hist(x,unique(x));
bins(N==3)

Of course you can save that output in the vector, y

y = bins(N==3);

Answer 2

[Zaki]

it's very helpful thank you very much :)

[Wayne King]

Can you accept the answer if it answered your question?