title: Replacing column data with Pandas .replace not working
body: <p>I am attempting to turn <a href="https://drive.google.com/file/d/1b_g03kXxpOPUzZeuJ3P03wGxP2JBkZuP/view?usp=sharing" rel="nofollow noreferrer">data from a .csv</a> into a Pandas df:</p>
  
  <pre><code>df = pd.read_csv('congress1.csv', delimiter = ';', names = ['Name', 'Years', 'Position', 'Party', 'State', 'Congress'], header = 0)
  </code></pre>
  
  <p>I want to replace the data in column "Congress" - "1(1789-1790)" - with a single date - "1789":</p>
  
  <pre><code>df['Congress'] = df['Congress'].replace('1(1789-1790)', '1789')
  </code></pre>
  
  <p>However, doing so does not change any of my data. If I, say, include inplace=True</p>
  
  <pre><code>df['Congress'] = df['Congress'].replace('1(1789-1790)', '1789', inplace=True)
  </code></pre>
  
  <p>... my data in that column of course becomes null. Yet I can't seem to replace this string with anything meaningful.</p>