title: pd.read_csv add column named "Unnamed: 0
body: <p>I have a dataframe with 3 columns.
  I save with <code>pd.to_csv(filename)</code>
  and then re-open it with </p>
  
  <pre><code>pd.read_csv(filename, index_col=False)
  </code></pre>
  
  <p>But I get a dataframe with 4 columns, with the left-most column called </p>
  
  <blockquote>
    <p>Unnamed:0</p>
  </blockquote>
  
  <p>that is actually just the row number.
  How can I read the csv without it?</p>
  
  <p>Thanks!</p>