title: Plot multiple columns on same plot
body: <pre><code>mydf &lt;- data.frame(
    id = 1:12,
    x = rnorm(12),
    y = rnorm(12),
    z = rnorm(12)
  )
  
  # base r
  plot(mydf$x)
  plot(mydf$y)
  plot(mydf$z)
  </code></pre>
  <p>One of these looks like e.g.</p>
  <p><a href="https://i.stack.imgur.com/54siQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/54siQ.png" alt="enter image description here" /></a></p>
  <p>what is the equivilent, if any in ggplot and can I display all 3 on one plot using color to separate them? Perhaps using a line?</p>
  <pre><code>mydf %&gt;% ggplot(aes(x)) + geom_point()
  Error: geom_point requires the following missing aesthetics: y
  </code></pre>