title: r: set labels for every point in xyplot {lattice} not for groups
body: <p>I am sure there is a simple solution for my question but I couldn't find my answer. I would like to <strong>put labels for every point value in scatterplot</strong> using lattice, not the basic plot. I found that the  <code>library(direct.label)</code> can complete this work, nice example here: <a href="http://directlabels.r-forge.r-project.org/examples.html" rel="nofollow noreferrer">http://directlabels.r-forge.r-project.org/examples.html</a>. 
  However, the labels here are displaying the name of the group, not display the value/name for every point! <strong>I would like to keep my data separated by groups (virginica, versicolor, setosa) but also add there exact value for every point (p.ex. Petal.Width) in the graph.</strong> Please, how to complete this? 
  Thank you a lot !</p>
  
  <pre><code>library(lattice)
  trellis.par.set(standard.theme(color=FALSE))
  p &lt;- xyplot(jitter(Sepal.Length)~jitter(Petal.Length),iris,groups=Species)
  direct.label(p)
  </code></pre>
  
  <p>what I do expect (the red values generated for every point):</p>
  
  <p><a href="https://i.stack.imgur.com/33MLr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/33MLr.png" alt="enter image description here"></a></p>