Binary random array with a specific proportion of ones?

Question

What is the efficient(probably vectorized with Matlab terminology) way to generate random number of zeros and ones with a specific proportion? Specially with Numpy?

Answer 1

If I understand your problem correctly, you might get some help with numpy.random.shuffle

>>> def rand_bin_array(K, N):
    arr = np.zeros(N)
    arr[:K]  = 1
    np.random.shuffle(arr)
    return arr

>>> rand_bin_array(5,15)
array([ 0.,  1.,  0.,  1.,  1.,  1.,  0.,  0.,  0.,  1.,  0.,  0.,  0.,
        0.,  0.])