d3.js 如何在条形图中添加线条

Posted 2023-02-22

【中文标题】d3.js 如何在条形图中添加线条

【英文标题】：d3.js How to add lines to a bar chart

【发布时间】：2012-10-25 05:20:01

【问题描述】：

我有一个包含 4 个值的数据集。 [A B C D]。目前，它们显示在条形图中，每个值一个条形。现在由于值 c 和 d 是平均值，我想将它们显示为 a 和 b 的条后面的线。 d3可以做到这一点吗？如何在同一个数据数组中切换条形或线形显示？

感谢您的帮助。

【参考方案1】：

从您的数据中创建具有两个属性的对象列表：

var data = [1,2,3,4];
var objects = data.slice(0, data.length/2).map(
  function(d,i)  return  value:d, average:data[i+data.length/2] ;  
);

然后你可以做这样的事情（未测试）：

var bars = chart.selectAll("g.bar")
   .data(objects)
  .enter().append("g")
    .attr("class", "bar")
    .attr("transform", function(d,i)  return "translate("+(i*10)+",0)"; );


bars.append("rect")
    .attr("x", 0)
    .attr("y", function(d,i)  return height - d.value; )
    .attr("width", 10)
    .attr("height", function(d,i)  return d.value; );

bars.append("line")
    .attr("x1", 0)
    .attr("y1", function(d,i)  return height - d.average; )
    .attr("x2", 10)
    .attr("y2", function(d,i)  return height - d.average; );

【参考方案2】：

我在这里发布一个示例，因为没有一个答案在 jsbin 或 jsfiddle 等中提供带线条的条形图的工作示例。http://jsbin.com/gisinomo/1/edit

该示例是 d3 wiki 上简单条形图的一个分支。http://bl.ocks.org/mbostock/3885304

CSS

body 
  font: 10px sans-serif;


.axis path,
.axis line 
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;


.bar 
  fill: steelblue;


.x.axis path 
  display: none;


.line 
  fill: none;
  stroke: #444;
  stroke-width: 1.5px;

JavaScript

var data = [ "letter": "A", "frequency": .08167,
 "letter": "B", "frequency": .01492,
 "letter": "C", "frequency": .02780,
 "letter": "D", "frequency": .04253,
 "letter": "E", "frequency": .12702,
 "letter": "F", "frequency": .02288,
 "letter": "G", "frequency": .02022,
 "letter": "H", "frequency": .06094,
 "letter": "I", "frequency": .06973,
 "letter": "J", "frequency": .00153,
 "letter": "K", "frequency": .00747,
 "letter": "L", "frequency": .04025,
 "letter": "M", "frequency": .02517,
 "letter": "N", "frequency": .06749,
 "letter": "O", "frequency": .07507,
 "letter": "P", "frequency": .01929,
 "letter": "Q", "frequency": .00098,
 "letter": "R", "frequency": .05987,
 "letter": "S", "frequency": .06333,
 "letter": "T", "frequency": .09056,
 "letter": "U", "frequency": .02758,
 "letter": "V", "frequency": .01037,
 "letter": "W", "frequency": .02465,
 "letter": "X", "frequency": .00150,
 "letter": "Y", "frequency": .01971,
 "letter": "Z", "frequency": .00074];

var margin = top: 20, right: 20, bottom: 30, left: 40,
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var formatPercent = d3.format(".0%");

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1);

var x2 = d3.scale.ordinal()
  .rangeBands([0, width], 0);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom"); 

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left")
    .tickFormat(formatPercent);

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 + ")");


  data.forEach(function(d) 
    d.frequency = +d.frequency;
  );

  x.domain(data.map(function(d)  return d.letter; ));
  x2.domain(data.map(function(d)  return d.letter; ));
  y.domain([0, d3.max(data, function(d)  return d.frequency; )]);

  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);

  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("Frequency");

  svg.selectAll(".bar")
      .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d)  return x(d.letter); )
      .attr("width", x.rangeBand())
      .attr("y", function(d)  return y(d.frequency); )
      .attr("height", function(d)  return height - y(d.frequency); );

var dataSum = d3.sum(data, function(d)  return d.frequency; ); 

 var line = d3.svg.line()
    .x(function(d, i)  
      return x2(d.letter) + i; )
    .y(function(d, i)  return y(dataSum/data.length); ); 

  svg.append("path")
      .datum(data)
      .attr("class", "line")
      .attr("d", line);

【讨论】：

@Martialp - 该行是原始的。我已经更新了小提琴和代码return x2(d.letter) 让它再次显示。