title: R join two dataframes but keep only one of duplicate columns
body: <p>I want to join two data frames which have some overlapping columns.  I am currently doing this like so:</p>
  
  <pre><code>library(dplyr)
  final &lt;-  full_join(df1, df2, by = "Id")
  </code></pre>
  
  <p>This works, except for the columns that both <code>df1</code> and <code>df2</code> have in common, it prefixes the shared columns with <code>.x</code> and <code>.y</code>.  What is the right way to join but keep only one instance of the shared column so no prefix is generated?</p>