带有一个对象键的d3饼图/value

Question

你好，我是d3和javascript的新手。我试图用一个填充多个键和值的对象来显示饼图。

我的目标是：

dataset Object { $Allied Health Professions, Dentistry, Nursing and Pharmacy: 4, $Psychology, Psychiatry and Neuroscience: 4, $Biological Sciences: 4, $General Engineering: 4, $Architecture, Built Environment and Planning: 4, $Geography, Environmental Studies and Archaeology: 4, $Business and Management Studies: 4, $Law: 4, $Social Work and Social Policy: 4, $Education: 4, 5 de plus… }

我的代码很长，在多个文件中，所以我不认为链接它是相关的。

我成功地用一个简单的数组加载了一个饼图，但是我不知道如何在这里访问这些值。

Answer 1

D3 data方法接受3件事情：

1. 阵列；
2. A功能；
3. 什么也没有；

因此，您必须在一个对象数组中转换该对象，其中一个特定属性用于类别，一个属性用于该值。例如：

​

var obj = {
  "Allied Health Professions, Dentistry, Nursing and Pharmacy": 4,
  "Psychology, Psychiatry and Neuroscience": 4,
  "Biological Sciences": 4,
  "General Engineering": 4,
  "Architecture, Built Environment and Planning": 4
};
var data = [];
for (var key in obj) {
  data.push({
    name: key,
    value: obj[key]
  })
};
console.log(data)

​

下面是一个包含部分对象的基本演示：

​

var obj = {
  "Allied Health Professions, Dentistry, Nursing and Pharmacy": 4,
  "Psychology, Psychiatry and Neuroscience": 4,
  "Biological Sciences": 4,
  "General Engineering": 4,
  "Architecture, Built Environment and Planning": 4
};
var data = [];
for (var key in obj) {
  data.push({
    name: key,
    value: obj[key]
  })
};
var arc = d3.arc().outerRadius(100).innerRadius(0);
var pie = d3.pie().value(function(d) {
  return d.value
});
var colors = d3.scaleOrdinal(d3.schemeCategory10)
var svg = d3.select("svg")
  .append("g")
  .attr("transform", "translate(100,100)")
svg.selectAll(null)
  .data(pie(data))
  .enter()
  .append("path")
  .attr("d", arc)
  .style("fill", function(d, i) {
    return colors(i)
  })

<script src="https://d3js.org/d3.v4.min.js"></script>
<svg width="200" height="200"></svg>

​