title: Creating legend with circles leaflet R
body: <p>I'm trying to create a leaflet map with points sized by a variable. Is it possible to create a legend with different sized circles representing the different variable values? I found another post showing how to convert squares to circles in the legend, but am not sure how to change the size of different circles in the legend. </p>
  
  <p>For example, here's a dummy script which creates 10 points associated with 2 classes of a variable (5 and 10). I'd like a legend with two circles the same size as that specified with addCircleMarkers with a radius of 5 and 10. If anyone can modify to create what I want I would be extremely grateful! Thanks!</p>
  
  <pre><code>library(shiny)
  library(leaflet)
  
  #create data
  Points&lt;-data.frame(x=runif(10,20,21), y=runif(10,0,1), var=rep(c(5,10),5))
  map = leaflet() %&gt;% addTiles()
  
  # Set up shiny app
  shinyApp(ui=bootstrapPage(
  tags$style(type = "text/css", "html, body {width:100%;height:100%}",
  ".leaflet .legend i{
  border-radius: 50%;
  width: 10px;
  height: 10px;
  margin-top: 4px;
  }
  "
  ),
  leafletOutput("myMap", width = "100%", height = "100%")),
  
  server= function(input, output){
  
  output$myMap = renderLeaflet({map %&gt;% 
      addCircleMarkers(Points$x,Points$y,radius=Points$var) %&gt;%
      addLegend(colors=rep("blue",2), labels=c(5,10))
    })
  })
  </code></pre>