无法从dc.js dataTable中删除空箱

时间:2017-07-11 17:30:48

标签: javascript dc.js crossfilter

我正在尝试删除空箱或者我应该在dc.js dataTable中说出0值的行。

我根据示例编写了我的代码&在dc.js文档的 remove empty bins常见问题解答中提供了一些片段,但我仍然无法获得所需的结果。

我正在尝试使用假组对数据进行分组,然后按总金额的降序对表进行排序。

var data = [{salesman: "AB",name: "John",total: 190.1,type: "Tab"}, 
            {salesman: "CD",name: "David",total: 190,type: "Tab"}, 
            {salesman: "EF",name: "Elton",total: 300.5,type: "Visa"}, 
            {salesman: "AB",name: "John",total: 90.0,type: "Tab"},
            {salesman: "EF",name: "Elton",total: 90,type: "Tab"}, 
            {salesman: "CD",name: "David",total: 90,type: "Tab"}];

var ndx = crossfilter(data);
var salesManDim = ndx.dimension(function(d) {
  return d.salesman;
});
var salesmanSumGroup = salesManDim.group().reduceSum(function(d) {
  return (Math.round((d.total) * 100) / 100);
});
var salesmanChart = dc.pieChart("#chart");
salesmanChart
  .width(200)
  .height(150)
  .slicesCap(10)
  .innerRadius(30)
  .dimension(salesManDim)
  .group(salesmanSumGroup);

var salesMan_TypeDim = ndx.dimension(function(d) {
  return d.salesman + "/" + d.type;
});
var groupedDimension = salesMan_TypeDim.group().reduce(
  function(p, v) {
    p.TOTAL += +(Math.round((v.total) * 100) / 100);
    p.SALESMAN = v.salesman + " - " + v.name;
    p.TYPE = v.type;
    return p;
  },
  function(p, v) {
    p.TOTAL -= +(Math.round((v.total) * 100) / 100);
    p.SALESMAN = v.salesman + " - " + v.name;;
    p.TYPE = v.type;
    return p;
  },
  function() {return { TOTAL: 0, SALESMAN: "",TYPE: ""};});

var rank = function(p) {
  return p.key.substr(p.key.lastIndexOf("/") + 1);
};

function remove_empty_bins(source_group) {
  function non_zero_pred(d) {
    return d.value.TOTAL !== 0;
  }
  return {
    top: function(n) {
      return source_group.top(Infinity).filter(non_zero_pred).slice(0, n);
    }
  };
}
dc.dataTable(".dc-data-table")
  .dimension(remove_empty_bins(groupedDimension))
  .group(rank)
  .size(Infinity)
  .columns([
    function(d) {
      return d.value.SALESMAN;
    },
    function(d) {
      return (Math.round((d.value.TOTAL) * 100) / 100);
    }
  ])
  .sortBy(function(d) {
    return d.value.TOTAL;
  })
  .order(d3.descending);
dc.renderAll();
dc.redrawAll();

当我检入调试器但是仍然以某种方式不过滤0值时,删除空箱功能正常工作。是因为我的键被定义的方式? To best explain my scenario here is a jsFiddle for the above example

1 个答案:

答案 0 :(得分:1)

令人惊讶的是,它出现在这样一个简单的例子中,但浮点加法和减法通常会导致值在你期望它们时不为零。

特别经常发生十进制数字。 0.1 is unrepresentable in binary floating point numbers, and they are not necessarily associative or distributive.

我们可以添加以下行来诊断问题:

  .on('preRedraw', function(chart) {
       console.log(chart.dimension().top(Infinity).map(x=>x.value.TOTAL));
  })

事实上,当我们点击CD时,我们会看到:

[200, 370.3, 2.842170943040401e-14]

所以这样写non_zero_pred

  function non_zero_pred(d) {
    return Math.abs(d.value.TOTAL) > 0.0001;
  }

零点消失了:https://jsfiddle.net/3fovopxp/7/

我现在要修复常见问题解答...