title: Error in UseMethod("group_by_") : no applicable method for 'group_by_' applied to an object of class "list"
body: <p>How do I group columns of a dataframe for each dataframe within a list of dataframes and apply group_by() and summarise()? </p>
  
  <p>Currently getting the error as show in the title. Here is what I have: </p>
  
  <p><a href="https://i.stack.imgur.com/i3jjF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/i3jjF.png" alt="enter image description here"></a></p>
  
  <p>I would like to <code>group_by()</code> and then <code>summarise()</code> as tried here: </p>
  
  <pre><code>trial &lt;- dataset %&gt;% group_by(Year) %&gt;% summarise(Mean_Max_Temp = mean(Max.Temp), Mean_Min_Temp = mean(Min.temp)
  +                                                             ,Monthly_Precip = sum(Precipitation))
  </code></pre>
  
  <p>Error in UseMethod("group_by_") : 
    no applicable method for 'group_by_' applied to an object of class "list"</p>