title: Convert float64 column to int64 in Pandas
body: <p>I tried to convert a column from data type <code>float64</code> to <code>int64</code> using:</p>
  
  <pre><code>df['column name'].astype(int64)
  </code></pre>
  
  <p>but got an error:</p>
  
  <blockquote>
    <p>NameError: name 'int64' is not defined</p>
  </blockquote>
  
  <p>The column has number of people but was formatted as <code>7500000.0</code>, any idea how I can simply change this <code>float64</code> into <code>int64</code>?</p>