Question

根据此example，我试图复制条形图。然后我有两个数据集：一个用于条形图，一个价格。

我想用单一价格做的就是按照条形来定位它。检查代码：

var price_data =  [
                              {'priceRangeStart':'4000000','numberOfProperties':100},
                              {'priceRangeStart':'4100000','numberOfProperties':256},
                              {'priceRangeStart':'4200000','numberOfProperties':773},
                              {'priceRangeStart':'4300000','numberOfProperties':334},
                              {'priceRangeStart':'4400000','numberOfProperties':587},
                              {'priceRangeStart':'4500000','numberOfProperties':400},
                              {'priceRangeStart':'4600000','numberOfProperties':700},
                              {'priceRangeStart':'4700000','numberOfProperties':150},
                              {'priceRangeStart':'4800000','numberOfProperties':229},
                              {'priceRangeStart':'4900000','numberOfProperties':500},
                              {'priceRangeStart':'5000000','numberOfProperties':125},
                              {'priceRangeStart':'5100000','numberOfProperties':170},
                              {'priceRangeStart':'5200000','numberOfProperties':290},
                              {'priceRangeStart':'5300000','numberOfProperties':660},
                              {'priceRangeStart':'5400000','numberOfProperties':450},
                              {'priceRangeStart':'5500000','numberOfProperties':359},
                              {'priceRangeStart':'5600000','numberOfProperties':740},
                              {'priceRangeStart':'5700000','numberOfProperties':894},
                              {'priceRangeStart':'5900000','numberOfProperties':547},
                              {'priceRangeStart':'6000000','numberOfProperties':1250}
                            ];

          var property_price = 5050000;


          var loadPriceComparisonChart = function (data, single_price) {

            // removing svg/tip artifacts
            d3.selectAll('.price-comparison-tip').remove();
            d3.select(elem[0]).select('svg').remove();

            // variables and helpers
            var margin = {top: 0, right: 20, bottom: 25, left: 0},
                width = 370,
                height = 200;

            var formatComma = d3.format(',');


            // responsive SVG
            // create responsive svg container for the graph
            var svg = d3.select(elem[0])
                  .append('div')
                  .classed('svg-price-comparison-container', true)
                  .append('svg')
                  .attr('preserveAspectRatio', 'none')
                  .attr('viewBox', '0 0 370 225')
                  //class to make it responsive
                  .classed('svg-content-responsive', true);

            // creating x and y scales
            var x = d3.scaleBand().rangeRound([0, width]).paddingOuter(0.5).paddingInner(0.6),
                x1 = d3.scaleBand().rangeRound([0, width]),
                y = d3.scaleLinear().rangeRound([height, 0]),
                y1 = d3.scaleLinear().rangeRound([0, (height - 100)]); //

            // creating the group object
            var g = svg.append('g')
                .attr('transform', 'translate(' + margin.left + ',' + margin.top + ')');

            // processing the data
            var new_dataset = data;
            var transformation = [];

            transformation = new_dataset.map(el => (
              {priceRangeStart: el.priceRangeStart, numberOfProperties: el.numberOfProperties}
            ));

            transformation.forEach(function(d) {
              d.priceRangeStart = +d.priceRangeStart;
              d.numberOfProperties = +d.numberOfProperties;
              return d;
            });

            // using lodash
            var minValue = _.first(transformation).priceRangeStart;
            var maxValue = _.last(transformation).priceRangeStart;

            // get max number of properties value
            var maxNrProperties = d3.max(transformation, function(d) {return d.numberOfProperties;});

            // x and y value domains
            x.domain(transformation.map(function(d) {console.log(d.priceRangeStart);return d.priceRangeStart;}));
            x1.domain(transformation.map(function(d) {return d.priceRangeStart;}));
            y.domain([0, ((d3.max(transformation, function(d) {return d.numberOfProperties;})) + (1.15 * maxNrProperties))]);
            y1.domain([0, (d3.max(transformation, function(d) {return d.numberOfProperties;}))]);

            // create x axis (for guiding purposes) and then hide it
            g.append('g')
                .attr('transform', 'translate(0,' + height + ')')
                .attr('class', 'axis axis--x')
                .call(d3.axisBottom(x))
                .style('opacity', 0)
                .selectAll('text').remove();

            // text for min price value and translate it to the start position of the first bar
            g.append('text')
              .attr('transform', 'translate(' + (x(_.first(transformation).priceRangeStart)) + ' ,' + (height * 1.1) + ')')
              .style('text-anchor', 'start')
              .style('font-size', '12px')
              .text('CHF ' + formatComma(minValue));

            // text for max price value and translate it to the end position of the last bar
            g.append('text')
              .attr('transform', 'translate(' + (x(_.last(transformation).priceRangeStart) + x.bandwidth()) + ' ,' + (height * 1.1) + ')')
              .style('text-anchor', 'end')
              .style('font-size', '12px')
              .text('CHF ' + formatComma(maxValue));

            // apppend the grey bars to the graph and styling them
            g.selectAll('.bar')
              .data(transformation)
              .enter().append('rect')
                .attr('class', 'bar')
                .attr('x', function(d) {return x(d.priceRangeStart);})
                .attr('y', function(d) {return height - y1(maxNrProperties);})
                .attr('width', x.bandwidth())
                .attr('height', function(d) {return y1(maxNrProperties);})
                .style('fill', '#A4A9AD')
                .style('opacity', 0.2);

            // apppend the orange bars to the graph and styling them
            g.selectAll(null)
              .data(transformation)
              .enter().append('rect')
                .attr('class', 'bar')
                .attr('x', function(d) {return x(d.priceRangeStart);})
                .attr('y', function(d) {return y(d.numberOfProperties);})
                .attr('width', x.bandwidth())
                .attr('height', function(d) {return height - y(d.numberOfProperties);})
                .style('fill', '#EDAA00')
                .style('opacity', 1);

            // append dashed line to show single property price position
            g.append('line')
              .attr('class', 'zero')
              .attr('x1', function(d) {return x1(single_price);})
              .attr('y1', function(d) {return  (y1(maxNrProperties) - 10);})
              .attr('x2', x(0))
              .attr('y2', function(d) {return height;})
              .style('stroke', '#003A5D')
              .style('stroke-width', 1)
              .style('stroke-dasharray', 6)
              .attr('transform', 'translate(30,0)');

正如您所看到的5050000的单一价格应该位于范围5000000和5100000的条形之间。单个价格应该是垂直虚线而不是另一个条形，如您在代码中看到的那样。问题是我无法正确定位。由于某种原因，我无法使用我为条形设置的x域。

最后，看起来应该是这样的：有什么想法吗？

Answer 1

当您将这些值用作分类（定性）变量时，使事情变得复杂。但是，有一个解决方案：

您可以使用x在d3.bisectLeft比例域中获得紧接该单一价格的价值：

var lineIndex = d3.bisectLeft(x.domain(), property_price);

然后，使用该索引获取该行的x位置：

.attr("x1", x(x.domain()[lineIndex]))
.attr("x2", x(x.domain()[lineIndex]))

以下是您更改的代码：

＆＃13;

var data = [{
  'priceRangeStart': '4000000',
  'numberOfProperties': 100
}, {
  'priceRangeStart': '4100000',
  'numberOfProperties': 256
}, {
  'priceRangeStart': '4200000',
  'numberOfProperties': 773
}, {
  'priceRangeStart': '4300000',
  'numberOfProperties': 334
}, {
  'priceRangeStart': '4400000',
  'numberOfProperties': 587
}, {
  'priceRangeStart': '4500000',
  'numberOfProperties': 400
}, {
  'priceRangeStart': '4600000',
  'numberOfProperties': 700
}, {
  'priceRangeStart': '4700000',
  'numberOfProperties': 150
}, {
  'priceRangeStart': '4800000',
  'numberOfProperties': 229
}, {
  'priceRangeStart': '4900000',
  'numberOfProperties': 500
}, {
  'priceRangeStart': '5000000',
  'numberOfProperties': 125
}, {
  'priceRangeStart': '5100000',
  'numberOfProperties': 170
}, {
  'priceRangeStart': '5200000',
  'numberOfProperties': 290
}, {
  'priceRangeStart': '5300000',
  'numberOfProperties': 660
}, {
  'priceRangeStart': '5400000',
  'numberOfProperties': 450
}, {
  'priceRangeStart': '5500000',
  'numberOfProperties': 359
}, {
  'priceRangeStart': '5600000',
  'numberOfProperties': 740
}, {
  'priceRangeStart': '5700000',
  'numberOfProperties': 894
}, {
  'priceRangeStart': '5900000',
  'numberOfProperties': 547
}, {
  'priceRangeStart': '6000000',
  'numberOfProperties': 1250
}];

var property_price = 5050000;

// variables and helpers
var margin = {
    top: 0,
    right: 20,
    bottom: 25,
    left: 0
  },
  width = 370,
  height = 200;

var formatComma = d3.format(',');


// responsive SVG
// create responsive svg container for the graph
var svg = d3.select("body")
  .append('svg')
  .attr('preserveAspectRatio', 'none')
  .attr('viewBox', '0 0 370 225')
  //class to make it responsive
  .classed('svg-content-responsive', true);

// creating x and y scales
var x = d3.scaleBand().rangeRound([0, width]).paddingOuter(0.5).paddingInner(0.6),
  x1 = d3.scaleBand().rangeRound([0, width]),
  y = d3.scaleLinear().rangeRound([height, 0]),
  y1 = d3.scaleLinear().rangeRound([0, (height - 100)]); //

// creating the group object
var g = svg.append('g')
  .attr('transform', 'translate(' + margin.left + ',' + margin.top + ')');

// processing the data
var new_dataset = data;
var transformation = [];

transformation = new_dataset.map(el => ({
  priceRangeStart: el.priceRangeStart,
  numberOfProperties: el.numberOfProperties
}));

transformation.forEach(function(d) {
  d.priceRangeStart = +d.priceRangeStart;
  d.numberOfProperties = +d.numberOfProperties;
  return d;
});

// using lodash
var minValue = _.first(transformation).priceRangeStart;
var maxValue = _.last(transformation).priceRangeStart;

// get max number of properties value
var maxNrProperties = d3.max(transformation, function(d) {
  return d.numberOfProperties;
});

// x and y value domains
x.domain(transformation.map(function(d) {
  return d.priceRangeStart;
}));
x1.domain(transformation.map(function(d) {
  return d.priceRangeStart;
}));
y.domain([0, ((d3.max(transformation, function(d) {
  return d.numberOfProperties;
})) + (1.15 * maxNrProperties))]);
y1.domain([0, (d3.max(transformation, function(d) {
  return d.numberOfProperties;
}))]);

// create x axis (for guiding purposes) and then hide it
g.append('g')
  .attr('transform', 'translate(0,' + height + ')')
  .attr('class', 'axis axis--x')
  .call(d3.axisBottom(x))
  .style('opacity', 0)
  .selectAll('text').remove();

// text for min price value and translate it to the start position of the first bar
g.append('text')
  .attr('transform', 'translate(' + (x(_.first(transformation).priceRangeStart)) + ' ,' + (height * 1.1) + ')')
  .style('text-anchor', 'start')
  .style('font-size', '12px')
  .text('CHF ' + formatComma(minValue));

// text for max price value and translate it to the end position of the last bar
g.append('text')
  .attr('transform', 'translate(' + (x(_.last(transformation).priceRangeStart) + x.bandwidth()) + ' ,' + (height * 1.1) + ')')
  .style('text-anchor', 'end')
  .style('font-size', '12px')
  .text('CHF ' + formatComma(maxValue));

// apppend the grey bars to the graph and styling them
g.selectAll('.bar')
  .data(transformation)
  .enter().append('rect')
  .attr('class', 'bar')
  .attr('x', function(d) {
    return x(d.priceRangeStart);
  })
  .attr('y', function(d) {
    return height - y1(maxNrProperties);
  })
  .attr('width', x.bandwidth())
  .attr('height', function(d) {
    return y1(maxNrProperties);
  })
  .style('fill', '#A4A9AD')
  .style('opacity', 0.2);

// apppend the orange bars to the graph and styling them
g.selectAll(null)
  .data(transformation)
  .enter().append('rect')
  .attr('class', 'bar')
  .attr('x', function(d) {
    return x(d.priceRangeStart);
  })
  .attr('y', function(d) {
    return y(d.numberOfProperties);
  })
  .attr('width', x.bandwidth())
  .attr('height', function(d) {
    return height - y(d.numberOfProperties);
  })
  .style('fill', '#EDAA00')
  .style('opacity', 1);

var lineIndex = d3.bisectLeft(x.domain(), property_price);

var line = svg.append("line")
  .attr("x1", x(x.domain()[lineIndex]) - x.step() / 2 + x.bandwidth() / 2)
  .attr("x2", x(x.domain()[lineIndex]) - x.step() / 2 + x.bandwidth() / 2)
  .attr("y1", height - 100)
  .attr("y2", height)
  .style("stroke", "gray")
  .style("stroke-width", 2)
  .style("stroke-dasharray", "2,2")

＆＃13;

<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>

＆＃13;

将垂直线添加到d3js条形图

1 个答案: