D3 Examples - Bar Chart: stripped easier

Bar Chart: stripped easier

This simple bar chart is constructed from a TSV file storing the frequency of letters in the English language. The chart employs conventional margins and a number of D3 features:

d3.tsv - load and parse data

d3.format - format percentages

d3.scale.ordinal - x-position encoding

d3.scale.linear - y-position encoding

d3.max - compute domains

d3.svg.axis - display axes

xxxxxxxxxx
 
<!DOCTYPE html>
<meta charset="utf-8">
<style>
​
.bar {
  fill: steelblue;
}
​
.bar:hover {
  fill: brown;
}
​
.axis {
  font: 10px sans-serif;
}
​
.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}
​
.x.axis path {
  display: none;
}
​
</style>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script>
  
// INSTRUCTIONS: everywhere there is "xxxxx", replace with code
​
var margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;
​
var xScale = 10;
​
​
var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
​
d3.tsv("data.tsv", type, function(error, data) {
  if (error) throw error;
​
  
  console.log(width);
  console.log(data.length);
  
  // increment for each
  xScale = width/data.length;
​
  var letters = data.map(function(d) { return d.letter; });
  var maxFrequency = d3.max(data, function(d) { return d.frequency; })
  
  yScale = d3.scale.linear().domain([0, maxFrequency]).range([0,height])
  
  // frequency is 0-1
  
  svg.selectAll(".bar")
      .data(data)
        .enter().append("rect")
      .attr("class", "bar")
      .attr("x", mapX)
      .attr("width", 20)
      .attr("y", mapY)
      .attr("height", mapH);
});
​
​
function mapX(d,i) {
   //console.log(i*10);
  return i * xScale;
}
​
 function mapY(d,i) {
  //-- in theory we'd map the frequency max
  return height - yScale(d.frequency)
}
  
function mapH(d,i) {
  //-- in theory we'd map the frequency max
  return yScale(d.frequency);
}
function type(d) {
  d.frequency = +d.frequency;
  return d;
}
​
</script>
​
    