title: how to for loop inside quote mark in R
body: <p>I am trying to loop like this.  </p>
  
  <pre><code> Ob.df&lt;-data.frame()
   Pt.df&lt;-data.frame()
  
   for(i in 1:10){
   AE.rf@models$PA$rf$`i`@evaluation$training@observed  -&gt;Ob.df[,i]
   AE.rf@models$PA$rf$`i`@evaluation$training@predicted -&gt;Pt.df[,i]
   }
  </code></pre>
  
  <p>however, the i goes inside quote mark ( <code>i</code> ) and it does not loop. 
  how to fix this issue?
  Thanks for your any help. </p>