Creating an array of objects efficiently in matlab

Question

Possible Duplicate:
How to preallocate an array of class in MATLAB?

I have a matlab code that create an array of objects of class X. X receives a single parameters: an integer.

The array of Xs is created from an array of indexes. Today I'm doing something like this:

for i=1:length(integer_array)
    integer = integer_array(i);
    cur_x = X(integer)
    x_arr = [x_arr cur_x];
end

Is there a more efficient way of doing this in Matlab?

Thanks