title: How to multiply every column in one dataframe with all columns in other dataframe
body: <p>I have two dataframes <code>X_dummy</code> and <code>X_var</code>, where <code>X_dummy</code> contains dummies and looks like this:</p>
  <pre><code>dummy1 dummy2 
   1       0     
   0       1      
   1       0      
  </code></pre>
  <p>The <code>X_var</code> dataframe looks contains variables and looks like this:</p>
  <pre><code>var1 var2 
   4    2    
   10   5    
   1    1    
  </code></pre>
  <p>Now I want to create a dataframe containing the cellwise product of every column from <code>X_dummy</code> with the complete <code>X_var</code> dataframe. Hence, my resulting dataframe should look like, <code>X_result</code>:</p>
  <pre><code>var1dummy1  var2dummy1  var1dummy2  var2dummy2  
  
      4           2           0          0                  
      0           0           10         5                     
      1           1           0          0                  
      
  </code></pre>
  <p>Does anyone know how to do this without using multiple for loops?</p>