title: Multiply each value in a pandas dataframe column with all values of 2nd dataframe column & replace each 1st dataframe value with resulting array
body: <p>I have a dataframe with 4 rows and 3 columns, and all values in this first dataframe (df1) are floats. I also have a second dataframe (df2) that has a column with 8760 entries. I would like to multiply each value in column 3 of the first dataframe by all 8760 values in the second dataframe. Finally, I want to replace the original value in the first dataframe by the resulting series of 8760 values (from multiplying each value by the 2nd dataframe values). So the values in column 3 of each row of the first dataframe are a resulting array of 8760 values.</p>
  <pre><code>data = {'col1':[1.0, 2.0, 1.0, 3.0], 'col2':[.01, .04, .8, 1.0], 'col3':[0.7, 0.1, 0.5, 0.9]}
  np.random.seed(123)
  
  df1 = pd.DataFrame(data) 
  df2 = pd.DataFrame(np.random.randint(0,10, size=(1,8760)))
  </code></pre>
  <p>So here I would like to take each value of col3 in df1 and replace with resulting array from multiplying that single value by all 8760 values in df2. So &quot;0.7&quot; would be replaced by an array of 8760 values from multiplying 0.7 by each value in df2. Is there an easy way to do this? When I tried, I just got the first value or NAN in df1 and not the array.</p>