initialize a numpy array

Question

Is there way to initialize a numpy array of a shape and add to it? I will explain what I need with a list example. If I want to create a list of objects generated in a loop,

Answer 1

I realize that this is a bit late, but I did not notice any of the other answers mentioning indexing into the empty array:

big_array = numpy.empty(10, 4)
for i in range(5):
    array_i = numpy.random.random(2, 4)
    big_array[2 * i:2 * (i + 1), :] = array_i

This way, you preallocate the entire result array with numpy.empty and fill in the rows as you go using indexed assignment.

It is perfectly safe to preallocate with empty instead of zeros in the example you gave since you are guaranteeing that the entire array will be filled with the chunks you generate.