title: Create 2D numpy array through nested loop
body: <p>I would like to create a 2D array using nested loop. What is the problem with this code?</p>
  
  <pre><code>import numpy
  
  b = np.array([])
  for i in range(2):
      for j in range(5):
          b[i][j]=i+j
  
  print(b)
  </code></pre>