Problem 214. Filter values in a vector

Cody often benefits from a functional style of programming. For example, your score is often better when you compose multiple functions instead of using intermediate variables. This problem involves creating a function to expand the repertoire of "functional functions."

For this problem, write a filter function that applies a "predicate" function to a numeric, character, or cell vector and returns the elements for which the predicate returns true. Here are few examples:

filterfun(@isprime, 1:10)                     ==> [2 3 5 7]
filterfun(@(c)c~='a', 'kayak radar')          ==> 'kyk rdr'
filterfun(@(x)~isempty(x), {[]; 1; 'a'; []; {}}') ==> {1; 'a'}

Notes: If the vector v is a cell, you should apply the predicate to v{i} not v(i). Also, filterfun should preserve the singleton dimension of the vector, i.e. if the input vector is a column vector the output should be a column vector.