title: What is the best way to tidily append many columns?
body: <p>I'm looking to append 30 columns which give values for gamma distributions by using the tidyverse. Here's an example of the data:</p>
  <pre><code>data.frame('rank'=1:3,'shape'=c(16,0.2,4),'rate'=c(13,0.4,0.2))
  </code></pre>
  <p>I'd like to use <code>dgamma(1:30,shape,rate)</code> to append 30 columns to the existing dataframe.</p>