Use a loop:
B = zeros(1, size(A, 2));
for column = 1 : size(A, 2)
B(column) = yourfunction(A(:, column));
end
Or you can use cellfun, which is just a loop in disguise:
B = cellfun(@yourfunction, num2cell(A, 1));
edit: That's assuming the function cannot already operate on the columns of the whole matrix, as pointed out by Star.
