title: Suppress print from summary on auto.arima model
body: <p>I checked the function <code>invisible</code> and <code>quietly</code> from the <code>purrr</code> package, but I couldn't work it out. I'm sorry if it has already been asked.</p>
  
  <p>I have something like this:</p>
  
  <pre><code>library(forecast)
  
  mod &lt;- auto.arima(AirPassengers)
  summary_mod &lt;- summary(mod) # this always makes a print of the summary
  rmse &lt;- summary_mod[2]
  </code></pre>
  
  <p>I wanted to save the rmse from the model, but with <code>summary</code> I can't find a way to kill the auto print function. </p>
  
  <p>I've tried:</p>
  
  <pre><code>summary_mod &lt;- invisible(summary(mod))
  
  library(purrr)
  summary_mod &lt;- quietly(summary(mod))
  </code></pre>
  
  <p>I've found out that I can use:</p>
  
  <pre><code>accuracy(mod)[2]
  # [1] 10.84619
  </code></pre>
  
  <p>But I was wondering if I can get a solution that suppress the <code>print</code> function, just for possible future needs.</p>