title: Length of each string in a NumPy array
body: <p>Is there any builtin operation in NumPy that returns the length of each string in an array?</p>
  
  <p>I don't think any of the <a href="https://docs.scipy.org/doc/numpy-1.12.0/reference/routines.char.html" rel="noreferrer">NumPy string operations</a> does that, is this correct?</p>
  
  <p>I can do it with a <code>for</code> loop, but maybe there's something more efficient?</p>
  
  <pre><code>import numpy as np
  arr = np.array(['Hello', 'foo', 'and', 'whatsoever'], dtype='S256')
  
  sizes = []
  for i in arr:
      sizes.append(len(i))
  
  print(sizes)
  [5, 3, 3, 10]
  </code></pre>