Question

如何找到每天的最低价值？维度为天，组为最小量。使用以下数据作为示例 -

var data = [
  {date: "2011-11-14T10:17:54Z", amount: 10 },
  {date: "2011-11-14T12:20:19Z", amount: 1 },
  {date: "2011-11-14T14:20:19Z", amount: 0 },
  {date: "2011-11-15T06:30:43Z", amount: 10 },
  {date: "2011-11-15T10:30:43Z", amount: 10 },
  {date: "2011-11-15T16:28:54Z", amount: 100 },
  {date: "2011-11-16T18:48:46Z", amount: 100 },
  {date: "2011-11-16T20:53:41Z", amount: 11 },
  {date: "2011-11-16T22:54:06Z", amount: 10 },
];

所以结果应该是 -

  {date: "2011-11-14T14:20:19Z", amount: 0 },
  {date: "2011-11-15T06:30:43Z", amount: 10 },
  {date: "2011-11-15T10:30:43Z", amount: 10 },
  {date: "2011-11-16T22:54:06Z", amount: 10 },

我试图解决这个问题，我现在完全糊涂了，所以任何帮助都会受到赞赏！

感谢。

Answer 1

以下内容将为您提供绝对最低要求。虽然不适用于过滤！

var data = [
  {date: "2011-11-14T10:17:54Z", amount: 10 },
  {date: "2011-11-14T12:20:19Z", amount: 1 },
  {date: "2011-11-14T14:20:19Z", amount: 0 },
  {date: "2011-11-15T06:30:43Z", amount: 10 },
  {date: "2011-11-15T10:30:43Z", amount: 10 },
  {date: "2011-11-15T16:28:54Z", amount: 100 },
  {date: "2011-11-16T18:48:46Z", amount: 100 },
  {date: "2011-11-16T20:53:41Z", amount: 11 },
  {date: "2011-11-16T22:54:06Z", amount: 10 },
];

var ndx = crossfilter(data);
var dayDim = ndx.dimension(function (d) { return "" + d.date.substr(8,2); });
var minGroup = dayDim.group().reduce(
  function (p, v) { if(v.amount < p || p === null) p = v.amount; return p; },
  function (p, v) { return p; },
  function () { return null; }
);

console.table(minGroup.top(Infinity));

如果要进行过滤，则需要保留每个数组中找到的所有值的排序数组，然后在过滤和未过滤数据时添加/删除值。然后使用这个排序的数组来计算出你的最小值。类似于以下内容（未经测试）：

var data = [
  {date: "2011-11-14T10:17:54Z", amount: 10 },
  {date: "2011-11-14T12:20:19Z", amount: 1 },
  {date: "2011-11-14T14:20:19Z", amount: 0 },
  {date: "2011-11-15T06:30:43Z", amount: 10 },
  {date: "2011-11-15T10:30:43Z", amount: 10 },
  {date: "2011-11-15T16:28:54Z", amount: 100 },
  {date: "2011-11-16T18:48:46Z", amount: 100 },
  {date: "2011-11-16T20:53:41Z", amount: 11 },
  {date: "2011-11-16T22:54:06Z", amount: 10 },
];

var ndx = crossfilter(data);
var dayDim = ndx.dimension(function (d) { return "" + d.date.substr(8,2); });
var minGroup = dayDim.group().reduce(
  function (p, v) { 
    if(v.amount < p.min || p.min === null) {
      p.min = v.amount;
    }
    p.values.push(v.amount);
    return p;
  },
  function (p, v) {
    p.values.splice(p.values.indexOf(v.amount),1);
    if(v.amount === p.min) {
      p.values.sort(function(a,b) { return a < b ? -1 : 1; });
      p.min = p.values[0];
    } 
    return p;
  },
  function () { return { min: null, values: [] }; }
);

console.log(minGroup.top(Infinity));

Crossfilter - 按天数计算的最小值

1 个答案: