title: How to create leaflet markers colored by a numeric variable
body: <p>I have a data frame with <code>latitude</code>, <code>longitude</code>, and a <code>number</code>. I want to add markers that are colored corresponding to these numbers. The numbers start at 1 and can be up to 100 or more.</p>
  
  <p>Optimally, I would like markers with a value &lt;= 1 to be orange, &lt;=10 to be dark orange, &lt;=50 to be red, and >=50 to be purple.</p>
  
  <p>This seems like a simple idea, but I can't quite figure it out. I tried to use the Awesome Icons (<em>though I would rather not</em>) from the <a href="https://rstudio.github.io/leaflet/markers.html" rel="nofollow noreferrer">leaflet site</a> (<em>scroll down to the if statement in the Awesome Icon section</em>), but that method was actually not working for me, and all the markers were red.</p>
  
  <pre><code>             lat            lon            number
  1       19.59917     -155.42009                 3
  2       22.21065     -159.47324               120
  3       22.21407     -159.59058                 7
  4       24.54509      -81.70717                49
  5       24.54630      -81.81060                 1
  6       24.55411      -81.80333                11
  </code></pre>
  
  <p>Above is sample data. It is part of a shiny app.</p>