title: correlation at the end of a pipe operation
body: <p>I am trying to get a correlation between two variables at the end of a pipe operation, why don't these work?</p>
  <pre><code>library(tidyverse)
  iris %&gt;% 
    map(~cor(.$Sepal.Length, .$Sepal.Width, use = &quot;complete.obs&quot;))
  
  #or
  iris %&gt;% 
    dplyr::select(Sepal.Length, Sepal.Width) %&gt;% 
    map2(~cor(.x, .y, use = &quot;complete.obs&quot;))
  </code></pre>
  <p>thanks</p>