title: How to multiply two columns in pandas, by only non-NaN values?
body: <p>I am curious if it is possible to multiply two columns <code>A,B</code> by only non NAN values.</p>
  
  <p>I have the following dataframe with the expected results: </p>
  
  <pre><code>                         A     B     C
      Date     Symbol  
  
    1/1/2017    BTC       Nan    2     Nan
                ETH        3     Nan   6
                XRP        2     Nan   4
    1/2/2017    BTC       Nan    3     Nan
                ETH        1     Nan    3
                XRP        2     Nan    6
  </code></pre>
  
  <p>I am trying to multiply non Nan values of column <code>A</code> by non-NaN values of Column <code>B</code> and assign the result to column <code>C</code>.
  I want to iterate over the dataframe. I have tried few things, but nothing is working.</p>