title: Multiplying the values in two columns: TypeError: can't multiply sequence by non-int of type 'float'
body: <p>I am trying to multiply the values in two separate columns</p>
  
  <p>The type of the elements in the first column is <code>'numpy.float64'</code></p>
  
  <p>That of the second column is <code>'float'</code></p>
  
  <p>When I do </p>
  
  <pre><code>new_column = df['first_column'] * df['second column']
  </code></pre>
  
  <p>I get </p>
  
  <blockquote>
    <p>'TypeError: can't multiply sequence by non-int of type 'float'</p>
  </blockquote>
  
  <p>I don't really understand why I cannot multiply the values of <code>numpy.float64</code> and <code>float</code>. Aren't they similar to each other and multipliable?</p>