title: Cant assign a plot to an object in R
body: <p>I recently opened some code I wrote a month or so ago suddenly when I try to assign an xyplot to a variable, it doesn't work. But I can still see the plot if I don't assign it to a variable.</p>
  
  <p>Example:</p>
  
  <pre><code>xyplot() #returns beautiful plot
  p1&lt;-xyplot() #returns nothing
  p2&lt;-xyplot() #returns nothing
  p1+p2 #returns "Error in p1 + p2 : non-numeric argument to binary operator"
  </code></pre>
  
  <p>I'm using R Studio, which I tried updating to solve the problem, but I have the same problem if I just run it in R as well. </p>
  
  <p>Is something wrong with my settings or how I am assigning/naming the objects? It took me a week to write my code to make these really pretty plots and now it doesn't work and I cant figure out why. I tried changing the object names so they don't have numbers, and I've googled the heck out of this. Any help is much appreciated.</p>