title: String slicing in numpy array
body: <p>Say we have an <code>numpy.ndarray</code> with <code>numpy.str_</code> elements. For example, below <code>arr</code> is the <code>numpy.ndarray</code> with two <code>numpy.str_</code> elements like this:</p>
  
  <pre><code>arr = ['12345"""ABCDEFG'  '1A2B3C"""']
  </code></pre>
  
  <p>Trying to perform string slicing on each numpy element.</p>
  
  <p>For example, how can we slice the first element <code>'12345"""ABCDEFG'</code> so that we replace its 10 last characters with the string <code>REPL</code>, i.e. </p>
  
  <pre><code>arr = ['12345REPL'  '1A2B3C"""']
  </code></pre>
  
  <p>Also, is it possible to perform string substitutions, e.g. substitute all characters after a specific symbol?</p>