title: Use the rows of two data frames as input for function, saving output as new data frame.
body: <p>I have two data frames, with identical number of columns but differing number of rows. I want to apply a function which outputs a value. The function uses one row of df1 against one row of df2 and outputs a single numerical value. I want to apply this function for every combination of rows possible between the two data frames and save the output as a new data frame.</p>
  
  <p>Can someone help me with this? Right now I'm doing it manually and it would take a very long time.</p>