title: memory usage: numpy-arrays vs python-lists
body: <p>Numpy is known for optimized arrays and various advantages over python-lists.
  But when I check for the memory usage python-lists have less space than the numpy arrays.
  The code I used is entered below.
  Can anyone explain me why?</p>
  <pre><code>import sys
  Z = np.zeros((10,10),dtype = int)
  A = [[0] * 10] * 10
  print(A,'\n',f'{sys.getsizeof(A)} bytes')
  print(Z,'\n',f'{Z.size * Z.itemsize} bytes')
  </code></pre>