Limiting vectors to a certain number of rows

Hi, i have created a function that creates n lots of a matrix of 3 columns but different number of rows. How do i limit the number of rows of this matrixes to say 4 for each one?

Answer 1

[Andrei Bobrov]

n = 7;

out = arrayfun(@(x)rand(randi(4),3),1:n,'un',0);