title: Outputting None instead of Values
body: <p>I am trying to utilize list comprehension to populate a new list, which is the length of text in a DataFrame column.</p>
  
  <p>So if the text is "electrical engineer", it should output 19 etc. Instead, it just fills the list with None values</p>
  
  <p>I have written out list comprehension below</p>
  
  <pre><code>all_text_length = [all_text_length.append(len(i)) for i in data['all_text']]
  </code></pre>
  
  <p>Expecting output of integer but its None</p>
  
  <p>As a workaround, I am currently using (successfully)</p>
  
  <pre><code>[all_text_length.append(len(i)) for i in data['all_text']]```
  </code></pre>