title: How to specify yaxs/xaxs='i' for axis() function?
body: <p>I am trying to specify a 4th axis:</p>
  
  <pre><code>axis(side=4, at=seq(0,4,1), yaxs='i')
  </code></pre>
  
  <p>I want this axis to start and end at the very top and bottom of the graph, similar to how you would code this in the <code>plot()</code> function, with <code>yaxs='i'</code>. However, <code>yaxs='i'</code> in the <code>axis()</code> function does nothing. Is there anything similar to <code>yaxs='i'/xaxs='i'</code> in the <code>axis()</code> function?</p>