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December 5, 2017 22:11
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Scatterplot (+linear regression, random)
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <svg width="960" height="500"></svg> | |
| <script src="https://d3js.org/d3.v4.min.js"></script> | |
| <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> | |
| <script> | |
| ;(function (d3, $) { | |
| window.drawScatterPlot = function () { | |
| var margin = {top: 20, right: 20, bottom: 30, left: 40} | |
| var width = 960 - margin.left - margin.right | |
| var height = 500 - margin.top - margin.bottom | |
| var xScale = d3.scaleLinear().range([0, width]) | |
| var yScale = d3.scaleLinear().range([height, 0]) | |
| var xAxis = d3.axisBottom().scale(xScale) | |
| var yAxis = d3.axisLeft().scale(yScale) | |
| var svg = d3.select('svg') | |
| .append('g') | |
| .attr('transform', 'translate(' + margin.left + ',' + margin.top + ')') | |
| xScale.domain(d3.extent(data, function (d) { return d.y })).nice() | |
| yScale.domain(d3.extent(data, function (d) { return d.x })).nice() | |
| svg.append('g') | |
| .attr('class', 'x axis') | |
| .attr('transform', 'translate(0,' + height + ')') | |
| .call(xAxis) | |
| svg.append('g') | |
| .attr('class', 'y axis') | |
| .call(yAxis) | |
| // regression | |
| let meanX = [] | |
| let meanY = [] | |
| Array.from(data).forEach(e => meanX.push(e.x)) | |
| Array.from(data).forEach(e => meanY.push(e.y)) | |
| meanX = _.mean(meanX) | |
| meanY = _.mean(meanY) | |
| let bTop = 0 | |
| let bBottom = 0 | |
| Array.from(data).forEach(e => { bTop += (e.x - meanX) * (e.y - meanY) }) | |
| Array.from(data).forEach(e => { bBottom += (Math.pow(e.x - meanX, 2)) }) | |
| const b = bTop / bBottom | |
| const a = meanY - b * meanX | |
| svg.append('line') | |
| .style('stroke', 'purple') | |
| .attr('x1', xScale(0)) | |
| .attr('y1', yScale(a + b * 0)) | |
| .attr('x2', xScale(9)) | |
| .attr('y2', yScale(a + b * 9)) | |
| // regression end | |
| svg.selectAll('.dot') | |
| .data(data) | |
| .enter() | |
| .append('circle') | |
| .attr('class', 'dot') | |
| .attr('r', 3.5) | |
| .attr('cx', function (d) { return xScale(d.y) }) | |
| .attr('cy', function (d) { return yScale(d.x) }) | |
| .attr('fill-opacity', '0') | |
| .attr('stroke-width', 1) | |
| .attr('stroke', function (d) { return (d.x > a + b * d.y) ? 'yellowgreen' : 'steelblue' }) | |
| } | |
| const data = [] | |
| for (let i = 0; i < 99; i++) { | |
| data.push({ | |
| 'x': d3.randomUniform(0, 9)(), | |
| 'y': d3.randomUniform(0, 9)(), | |
| }) | |
| } | |
| }(window.d3, window.$)) | |
| </script> | |
| <script>drawScatterPlot()</script> |
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