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

Another way of getting the exact number of ones and zeroes is to sample indices without replacement using np.random.choice:

arr_len = 30
num_ones = 8

arr = np.zeros(arr_len, dtype=int)
idx = np.random.choice(range(arr_len), num_ones, replace=False)
arr[idx] = 1

Out:

arr

array([0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1,
       0, 0, 0, 0, 0, 1, 0, 0])