title: Slicing the values of object type in data frame
body: <p>I have a DataFrame where all of the values in the column show the <em>Date of Publication</em></p>
  <p><a href="https://i.stack.imgur.com/f1ifw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/f1ifw.png" alt="enter image description here" /></a></p>
  <p>I need to remove an additional text to have the following result:</p>
  <p>From:</p>
  <blockquote>
  <p>1879 [1879]</p>
  </blockquote>
  <p>To</p>
  <blockquote>
  <p>1879</p>
  </blockquote>
  <p>I have checked the datatype and god the following result:</p>
  <pre><code>Identifier               int64
  Edition Statement       object
  Place of Publication    object
  Date of Publication     object
  Publisher               object
  Title                   object
  Author                  object
  Contributors            object
  Flickr URL              object
  dtype: object
  </code></pre>
  <p>Finally, I have tried the following method but it did not work for me.</p>
  <pre><code>new_books = books['Date of Publication'].astype(object).apply(lambda x: x.str.slice(0, 3))
  </code></pre>
  <p>What am I doing wrong?</p>