title: Same value getting counted twice in dataframe.value_counts, the data
body: <p>I am working with a very simple dataset, which has a feedback column with string inputs, I then converted all values into lower and did a simple valuecounts to see the distribution but this is happening</p>
  <pre><code>nc            28
  others        27
  undecided      5
  na             2
  ni             1
  undecided      1
  Name: FeedBack, dtype: int64
  </code></pre>
  <p>I tried these 2 things did'nt work</p>
  <ol>
  <li><code>df['FeedBack'] = df['FeedBack'].replace('undecided', 'undecided')</code></li>
  <li><code>df.FeedBack=df.FeedBack.apply(lambda x: str(x).lower())</code>
  The data type is showing object despite the explicit typecasting.</li>
  </ol>
  <p>Thanks</p>
  <p>Sruthi</p>