D3 Examples - Cleaned bar chart: Free and reduced lunch in IA

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<html lang="en">
    <head>
        <meta charset="utf-8">
        <title>Free and reduced lunch in Iowa</title>
        <script type="text/javascript" src="https://d3js.org/d3.v3.js"></script>
    </head>
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    <link rel="stylesheet" type="text/css" href="styles.css">
    <body>
        <h3>Free and reduced lunch in Iowa</h3>
        <p>This graph shows all the schools in Iowa where 50% or more of their students are on a free or reduced lunch program. A total of 64 school districts are shown. To download the data, <a href="https://docs.google.com/spreadsheets/d/1KvLX4M8ww2js4GMWOX4niM9fApu0efvc59pLKAyeM-s/" target="_blank">click here</a>.</p>
        <svg></svg>
​
        <script type="text/javascript">     
            var width = 500;
            var height = 1000;
            var padding = [0, 15, 25, 150];
​
            // Determines width of bars
            // Based on data values
            var widthScale = d3.scale.linear()
                // This is what is outputted
                .range([ 0, width - padding[1] - padding[3] ]);
​
            // Determines height of bars
            // Based on number of values total
            var heightScale = d3.scale.ordinal()
                // This is what is outputted
                .rangeRoundBands([ padding[0], height - padding[2] ], 0.15);
​
            var xAxis = d3.svg.axis()
                .scale(widthScale)
                .orient("bottom");
​
            var yAxis = d3.svg.axis()
                .scale(heightScale)
                .orient("left");
​
            // Create empty SVG so we can append data to it later
            var svg = d3.select("svg")
                .attr("width", width)
                .attr("height", height);
​
            // Load CSV data
            d3.csv("ia_free_reduced_50_higher.csv", function(data) {
                // Sort desc
                data.sort(function(a, b) {
                    return d3.descending(+a['Percent'], +b['Percent'] );
                });
​
                // Set second domain to max value in data
                widthScale.domain([ 0, d3.max(data, function(d) {
                    return +d['Percent'];
                }) ]);
​
                // Map school name to school value
                heightScale.domain(data.map(function(d) {
                    return d['Name'];
                } ));
​
                // Create rectangles and append to DOM
                var rects = svg.selectAll("rect")
                    .data(data)
                    .enter()
                    .append("rect");
​
                // Set attributes
                rects.attr("x", padding[3])
                    .attr("y", function(d, num) {
                        return heightScale( d['Name'] );
                    })
                    .attr("width", function(d) {
                        return widthScale( d['Percent'] );
                    })
                    .attr("height", heightScale.rangeBand())
                    .append("title")
                    // Tooltip
                    .text(function(d) {
                        return 'The percentage of students on free or reduced lunch at ' + d['Name'] + 'High School is ' + d['Percent'] + '%.';
                    });
​
                // Append x and y axis
                svg.append("g")
                    .attr("class", "x-axis axis")
                    .attr("transform", "translate(" + padding[3] + "," + (height - padding[2]) + ")")
                    .call(xAxis);
​
                svg.append("g")
                    .attr("class", "y-axis axis")
                    .attr("transform", "translate(" + padding[3] + ",0)")
                    .call(yAxis);
            });
        </script>
    </body>
</html>
    