title: Error message when running simple 'rename' function in R
body: <p>Below a very simple data frame example I found in the internet. Running this in RStudio on my machine turns out an error message: </p>
  
  <blockquote>
    <p>Error: All arguments to rename must be named. </p>
  </blockquote>
  
  <p>The <code>rename</code> function seems to be straight forward but doesn't work for some reasons and I can't figure out why.</p>
  
  <pre><code>library("dplyr")
  
  d &lt;- data.frame(alpha=1:3, beta=4:6, gamma=7:9)
  d
  #   alpha beta gamma
  # 1     1    4     7
  # 2     2    5     8
  # 3     3    6     9
  
  rename(d, c("beta"="two", "gamma"="three"))
  
  #Error: All arguments to rename must be named.
  </code></pre>