title: Expression label in visnetwork r
body: <p>Is it possible to use expression for subscript or superscript at the node label in vis network?
  Or is it possible to change the label after the plot?</p>
  
  <pre><code> nodes &lt;- data.frame(id = 1:10,
  
                  # add labels on nodes
                  label = paste("N[", 1:10,"]", sep = ""),
  
                  # add groups on nodes 
                  group = c("GrA", "GrB"),
  
                  # size adding value
                  value = 1:10,          
  
                  # control shape of nodes
                  shape = c("square", "triangle", "box", "circle", "dot", "star",
                            "ellipse", "database", "text", "diamond"),
  
                  # tooltip (html or character), when the mouse is above
                  title = paste0("&lt;p&gt;&lt;b&gt;", 1:10,"&lt;/b&gt;&lt;br&gt;Node !&lt;/p&gt;"),
  
                  # color
                  color = c("darkred", "grey", "orange", "darkblue", "purple"),
  
                  # shadow
                  shadow = c(FALSE, TRUE, FALSE, TRUE, TRUE))             
  
  # head(nodes)
  # id  label group value    shape                     title    color shadow
  #  1 Node 1   GrA     1   square &lt;p&gt;&lt;b&gt;1&lt;/b&gt;&lt;br&gt;Node !&lt;/p&gt;  darkred  FALSE
  #  2 Node 2   GrB     2 triangle &lt;p&gt;&lt;b&gt;2&lt;/b&gt;&lt;br&gt;Node !&lt;/p&gt;     grey   TRUE
  
  edges &lt;- data.frame(from = c(1,2,5,7,8,10), to = c(9,3,1,6,4,7))
  
  visNetwork(nodes, edges, height = "500px", width = "100%")
  </code></pre>