title: R: math notation in data.frame
body: <pre><code>&gt; df = data.frame(Parameters = c(expression(beta[1])))
  Error in as.data.frame.default(x[[i]], optional = TRUE) : 
    cannot coerce class ""expression"" to a data.frame
  </code></pre>
  
  <p>I'm trying to write math notation in a data.frame, but it seems that the two are not compatible. Is there a way around this?</p>
  
  <p>I have also tried</p>
  
  <pre><code>&gt; data.frame(Parameters = paste(expression(beta[1])))
    Parameters
  1    beta[1]
  </code></pre>
  
  <p>How can I get <a href="https://i.stack.imgur.com/fhRGe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/fhRGe.png" alt="enter image description here"></a> to show up?</p>