javascript - JSON 中出现次数的条形图

Question

我有一个政客的 JSON，一个包含他们的姓名和政党的列表。

很简单，我想做的是制作一个条形图，条形的大小取决于来自不同政党的政客的数量。

按键看起来像这样:

{
    "party": "National Liberal Party – True Liberalism",
    "region": "london",
    "name": "Bernard Dube",
    "twitter": ""
  },
  {
    "party": "Alliance Party of Northern Ireland",
    "region": "northern-ireland",
    "name": "Anna Lo",
    "twitter": "Anna4Europe"
  },

不幸的是，它并不那么简单:

{
"National Liberal Party": "330", 
"Alliance Party of Northern Ireland": "200"
}

如何使用 d3 做到这一点？谢谢!

Answer 1

构建你想要的数据:

var d = {};
records.forEach(function(i)  {
  if(d[i.party] == null) {
    d[i.party] = 0;
  }
  d[i.parts] += 1;
});