D3.js using data from csv file to populate svg map

Question

I have an svg map with each path having a class="county-code-###".

Also have an csv file with the county-name, county-code and county population.

I have the following started but not sure how to populate the correct path with the date coming from the csv.

    d3.text("counties.csv", function (datasetText) {

        var parsedCSV = d3.csv.parseRows(datasetText);

        var sampleHTML = d3.select("div")
            .append("div")
            .style("")
            .style("")

        .selectAll("path")
            .data(parsedCSV)
            .enter().append("path")

    });

Answer 1

You can use the datum method to add the name of the region (and the id) to the data. Something like:

<script>
  var height = 500;
  var width = 700;

  // generate a sample 'map'. This svg does not contain the names of the 
  // regions
  var data = [{id:1, x:10, y:10}, {id:2, x:300, y:400}, {id:3, x:600, y:100}];
  var vis = d3.select("#vis").append("svg")
    .attr("width", width).attr("height", height);
  vis.selectAll("rect").data(data).enter().append("rect")
    .attr("x", function(d) { return d.x;})
    .attr("y", function(d) { return d.y;})
    .attr("width", 20).attr("height", 20)
    .attr("class", function(d) { return "county-code-" + d.id;});

  // Some sample data containing the region names; in this case hard coded, 
  // but could also be read from a csv file. 
  var data2 = [{id:1, name:"a"}, {id:2, name:"b"}, {id:3, name:"c"}];

  // Add the names to the svg
  vis.selectAll("rect").datum(function(d) {
    // extract county code from class
    var id = +d3.select(this).attr("class").match(/county-code-(\d+)/)[1];
    d.id = id;
    // look up id in data2; if found add name to datum
    for (var i = 0; i < data2.length; i++) {
      if (data2[i].id == id) {
        d.name = data2[i].name;
        break;
      }
    }
    return d;
  });


</script>