Appending to the rows and columns to Multi dimensional Arrays Numpy Python

Question

I am trying to append to create a multi dimensional array where it inputs 4 random numbers per row. The code below does not work. How would I be able to fix it?

import numpy as np
import random 

Array = np.array([[]])

for i in range(3):
    for k in range(4):
        Array[i][k]= np.append(Array[i][k], random.randint(0,9))

Expected Output:

[[1,3,4,8],
 [2,3,6,4],
 [7,4,1,5],
 [8,3,1,1]]

Answer 1

Don't do this . It is highly inefficient to try to create an array like this incrementally using np.append. If you must do something like this, use a np.append. If you must do something like this, use a list and then convert the resulting list to a numpy.ndarray` later.

However, in this case, you simply want:

>>> import numpy as np
>>> np.random.randint(0, 10, (3,4))
array([[0, 3, 7, 4],
       [6, 4, 2, 2],
       [4, 4, 0, 6]])

Or perhaps:

>>> np.random.randint(0, 10, (4,4))
array([[8, 8, 2, 7],
       [3, 7, 2, 1],
       [5, 5, 5, 5],
       [6, 2, 7, 9]])

Note, np.random.randint has an exclusive end, so if you want to draw from numbers [0, 9] you need to use 9+1 as the end.