title: How do you map every combination of categorical variables in R?
body: <p>Using R, is there a way to take a data set and map out every possible combination of every categorical variable? </p>
  
  <p>For example, let's say I had 10,000 rows of customer data from an online shop. I want to find out which shoppers spend the most money. I have the following data from the customer:</p>
  
  <p>E-mail (yahoo, gmail, hotmail, aol)
  Browser (Mozilla, IE, Chrome, Opera)
  Country (USA, Canada, China, Australia, Egypt, S.Korea, Brazil)
  How much total money each user spent at my store.</p>
  
  <p>I want to graph out every possible combination of the above three categorical variables and see what was the average spending of each customer.</p>
  
  <p>What is a good way to do this in R? (note: my R experience is average right now)</p>
  
  <p>Thanks.</p>