[introd3] scatterplot random data by romsson

index.html

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

<body>
  <script>
    var svg = d3.select("body").append("svg")
      .attr("width", 960)
      .attr("height", 500)

    var data = d3.range(100).map(function(d) {
      return {"x": Math.random(), 
              "y": Math.random(), 
              "cat": Math.floor(Math.random() * 3) 
             }
    });
    
    var x = d3.scaleLinear()
    	.domain([0, d3.max(data, function(d) { return d.x; })])
    	.range([200, 600]);

    var y = d3.scaleLinear()
    	.domain([0, d3.max(data, function(d) { return d.y; })])
    	.range([100, 400]);

		var color = d3.scaleOrdinal(d3.schemeCategory20);
    
    x.domain(d3.extent(data, function(d) { return d.x; }))
    y.domain(d3.extent(data, function(d) { return d.y; }))
      
    svg.selectAll("circle").data(data).enter()
    .append("circle")
    	.style("fill", function(d, i) { return color(d.cat); })
    	.style("stroke", "black")
    	.attr("r", 10)
    	.attr("cx", function(d) { return x(d.x); })
    	.attr("cy", function(d) { return y(d.y); });
    
  </script>
</body>