Florida 2016 Age by District (Grouped Bar Chart)

This grouped bar chart is constructed from a CSV file storing the populations of different districts by age group. The chart employs conventional margins and a number of D3 features:

d3.csv - load and parse data
d3.scale.ordinal - x-position encoding and color encoding
d3.scale.linear - y-position encoding
d3.format - SI prefix formatting (e.g., “10M” for 10,000,000)
d3.max - compute domains
d3.keys - compute column names
d3.svg.axis - display axes

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<!DOCTYPE html>
<style>

.axis .domain {
  display: none;
}

</style>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
    margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom,
    g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var x0 = d3.scaleBand()
    .rangeRound([0, width])
    .paddingInner(0.1);

var x1 = d3.scaleBand()
    .padding(0.05);

var y = d3.scaleLinear()
    .rangeRound([height, 0]);

var z = d3.scaleOrdinal()
    .range(["#98abc5", "#8a89a6", "#7b6888", "#6b486b", "#865361", "#a05d56", "#d0743c", "#ff8c00", "#CC9C63"]);

d3.csv("data.csv", function(d, i, columns) {
  for (var i = 1, n = columns.length; i < n; ++i) d[columns[i]] = +d[columns[i]];
  return d;
}, function(error, data) {
  if (error) throw error;

var keys = data.columns.slice(1);

x0.domain(data.map(function(d) { return d.District; }));
  x1.domain(keys).rangeRound([0, x0.bandwidth()]);
  y.domain([0, d3.max(data, function(d) { return d3.max(keys, function(key) { return d[key]; }); })]).nice();

g.append("g")
    .selectAll("g")
    .data(data)
    .enter().append("g")
      .attr("transform", function(d) { return "translate(" + x0(d.District) + ",0)"; })
    .selectAll("rect")
    .data(function(d) { return keys.map(function(key) { return {key: key, value: d[key]}; }); })
    .enter().append("rect")
      .attr("x", function(d) { return x1(d.key); })
      .attr("y", function(d) { return y(d.value); })
      .attr("width", x1.bandwidth())
      .attr("height", function(d) { return height - y(d.value); })
      .attr("fill", function(d) { return z(d.key); });

g.append("g")
      .attr("class", "axis")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x0));

g.append("g")
      .attr("class", "axis")
      .call(d3.axisLeft(y).ticks(null, "s"))
    .append("text")
      .attr("x", 2)
      .attr("y", y(y.ticks().pop()) + 0.5)
      .attr("dy", "0.32em")
      .attr("fill", "#000")
      .attr("font-weight", "bold")
      .attr("text-anchor", "start")
      .text("Percent");

var legend = g.append("g")
      .attr("font-family", "sans-serif")
      .attr("font-size", 10)
      .attr("text-anchor", "end")
    .selectAll("g")
    .data(keys.slice().reverse())
    .enter().append("g")
      .attr("transform", function(d, i) { return "translate(0," + i * 20 + ")"; });

legend.append("rect")
      .attr("x", width - 19)
      .attr("width", 19)
      .attr("height", 19)
      .attr("fill", z);

legend.append("text")
      .attr("x", width - 24)
      .attr("y", 9.5)
      .attr("dy", "0.32em")
      .text(function(d) { return d; });
});

</script>

https://d3js.org/d3.v4.min.js