title: ValueError: Length of values does not match length of index | Pandas DataFrame.unique()
body: <p>I am trying to get a new dataset, or change the value of the current dataset columns to their unique values.
  Here is an example of what I am trying to get :</p>
  <pre><code>   A B
   -----
  0| 1 1
  1| 2 5
  2| 1 5
  3| 7 9
  4| 7 9
  5| 8 9
  
  Wanted Result    Not Wanted Result
         A B            A B
       -----          -----
      0| 1 1         0| 1 1
      1| 2 5         1| 2 5
      2| 7 9         2| 
      3| 8           3| 7 9
                     4|
                     5| 8
  </code></pre>
  <p>I don't really care about the index but it seems to be the problem.
  My code so far is pretty simple, I tried 2 approaches, 1 with a new dataFrame and one without.</p>
  <pre><code>#With New DataFrame
  def UniqueResults(dataframe):
      df = pd.DataFrame()
      for col in dataframe:
          S=pd.Series(dataframe[col].unique())
          df[col]=S.values
      return df
  
  #Without new DataFrame
  def UniqueResults(dataframe):
      for col in dataframe:
          dataframe[col]=dataframe[col].unique()
      return dataframe
  </code></pre>
  <p>I have the error &quot;Length of Values does not match length of index&quot; both times.</p>