I'm having trouble with formatting when using tooltips (or labels?) in D3.js
<p>I’m totally noob-tastic (i.e. I have very little programming background and am trying to hack together a dashboard using borrowed code) but I am eager to learn more!</p>

<p>I’m currently hung up with what I hope is a small issue. 
I’m using a version of Bostock’s calendar example...</p>

<p><a href="http://i.stack.imgur.com/miGfq.png" rel="nofollow">calendar</a></p>

<p>...and have managed to get close to my desired outcome but I’m having trouble with the tooltip(?), specifically the second .attr under rect.filter below.</p>

<pre><code>    d3.csv("BugeseraData.csv", function(error, csv) {

  csv.forEach(function(d) {
    d.Daily_total = parseInt(d.Daily_total);
  });

 var Daily_total_Max = d3.max(csv, function(d) { return d.Daily_total; });

  var data = d3.nest()
    .key(function(d) { return d.Date1; })
    .rollup(function(d) { return  Math.sqrt(d[0].Daily_total / Daily_total_Max); })
    .map(csv);


  rect.filter(function(d) { return d in data; })
      .attr("fill", function(d) { return color(data[d]); })
      .attr("data-title", function(d) { return 'RwF ' +d  });
    $("rect").tooltip({container: 'body', html: true, placement:'top'}); 
});
</code></pre>

<p>The data has been imported from a .csv and has two “columns” (I'm using excel), titled 'Date1' and 'Daily_total' respectively.</p>

<p>When you mouse over a particular day I want to to return “RwF” + the value from the second column (the amount or Daily_total). </p>

<p><a href="http://i.stack.imgur.com/uO0Eh.png" rel="nofollow">like this</a></p>

<p>Currently, the “RwF” shows up but when I use d.Daily_total (the second column) the result is returning as “RwF undefined”. If I use “RwF” + d then I get “RwF” with the date (the value from the first column). </p>

<p>Would someone please help me understand the correct way to achieve this?</p>

<p>This is data from local government revenue collection and I want to be able to show collection amounts by day at a  glance. I want the actual collection amounts (not the date) to show upon mouseover.</p>

<p>Thank you!</p>