title: convertion and triming of numpy array of lists to numpy array of numpy arrays problem
body: <p>hey I'm new to numpy arrays and I have a short code I would like to understand, i tried to convert a numpy array of lists to numpy array of numpy arrays, </p>
  
  <pre><code>a=np.array([[1,2,3],[3,2,3,4]])
  for i in range(len(a)):
      if len(a[i])&gt;3:
          a[i]=a[i][:3]
      a[i]=np.array(a[i])
  </code></pre>
  
  <p>now i checked the types of a and a[0] and a[1] and all are numpy arrays.
  then <strong>i printed the shape of a and it was (2,) and not (2,3) like i expected it to be</strong> although a[0] and a[1] lengths are the same, so i would like to know why it happens and how could i convert the variable a from a numpy array of lists to a numpy array of numpy array with the shape (2,3) for example, thank you very much for your help.</p>