title: How to convert integer array to list using python pandas
body: <p>I had a dataframe column like as shown below</p>
  <pre><code>col1
  &lt;NA&gt;
  123.23
  453.21
  567.21
  879.21
  </code></pre>
  <p>To convert float with NaN into integer, I did the below</p>
  <pre><code>df['col1'].astype(float).astype('Int64')
  </code></pre>
  <p>When I do the below</p>
  <pre><code>df['col1'] = df['col1'].fillna(0)
  df['col1'].unique().tolist()
  </code></pre>
  <p>I get the following error</p>
  <pre><code>AttributeError: 'IntegerArray' object has no attribute 'tolist'
  </code></pre>