使用交叉过滤器在 JavaScript 中动态返回结果

Using crossfilter to dynamically return results in JavaScript

本文关键字：动态 返回 结果 JavaScript 过滤器      更新时间：2023-09-26

我觉得交叉过滤器库 API 解释是为我的技能集以上的人编写的，但我也知道掌握它会解决我的问题。

为简单起见，我将在此问题中引用 API 页面的示例数据。

var payments = crossfilter([
  {date: "2011-11-14T16:17:54Z", quantity: 2, total: 190, tip: 100, type: "tab"},
  {date: "2011-11-14T16:20:19Z", quantity: 2, total: 190, tip: 100, type: "tab"},
  {date: "2011-11-14T16:28:54Z", quantity: 1, total: 300, tip: 200, type: "visa"},
  {date: "2011-11-14T16:30:43Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T16:48:46Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T16:53:41Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T16:54:06Z", quantity: 1, total: 100, tip: 0, type: "cash"},
  {date: "2011-11-14T16:58:03Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T17:07:21Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T17:22:59Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T17:25:45Z", quantity: 2, total: 200, tip: 0, type: "cash"},
  {date: "2011-11-14T17:29:52Z", quantity: 1, total: 200, tip: 100, type: "visa"}
]);

我能够返回与特定键（数量、总数等）匹配的记录，但我不明白如何返回与键/值对组合匹配的结果。例如，我将如何返回与数量大于 1、总计等于 90、提示等于 0 和选项卡类型匹配的结果集？这就是我完全迷失的地方。

您可以为每个属性创建一个维度，然后使用您指定的相应筛选条件调用每个维度的筛选方法，如下所示。

var payments_by_quantity = payments.dimension(function(d){return d.quantity}),
    payments_by_total = payments.dimension(function(d){return d.total}),
    payments_by_tip = payments.dimension(function(d){return d.tip}),
    payments_by_type = payments.dimension(function(d){return d.type});
payments_by_quantity.filter([1, Infinity]);
payments_by_total.filter(90);
payments_by_tip.filter(0);
payments_by_type.filter("tab");
payments_by_type.top(Infinity)

效果是累积的，因此最后一行实际上是所有值的结果，这些值都遵循所有维度的所有过滤器。

我发现上面的答案很精确，但对我来说是初学者，即我没有得到或意想不到的结果（没有不尊重 slo-jo，但我是从初学者的角度写的，因为我是一个交叉过滤器 nube）。陷阱是在调用某些过滤器之前需要清除过滤器（您需要使用更多种类扩展数据集，例如不同的提示、总数等，以了解我的意思）。输出到控制台对我有帮助。

以下是有助于我理解的内容：

    var data = [
  {date: "2011-11-14T16:17:54Z", quantity: 2, total: 190, tip: 100, type: "tab"},
  {date: "2011-11-14T16:20:19Z", quantity: 2, total: 190, tip: 100, type: "tab"},
  {date: "2011-11-14T16:28:54Z", quantity: 1, total: 300, tip: 200, type: "visa"},
  {date: "2011-11-14T16:30:43Z", quantity: 222, total: 990, tip: 0, type: "tab"},
  {date: "2011-11-14T16:48:46Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T16:53:41Z", quantity: 5, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T16:54:06Z", quantity: 1, total: 100, tip: 0, type: "cash"},
  {date: "2011-11-14T16:58:03Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T17:07:21Z", quantity: 2, total: 90, tip: 0, type: "tab"},
  {date: "2011-11-14T17:22:59Z", quantity: 2, total: 990, tip: 0, type: "tab"},
  {date: "2011-11-14T17:25:45Z", quantity: 2, total: 200, tip: 0, type: "cash"},
  {date: "2011-11-14T17:29:52Z", quantity: 1, total: 200, tip: 100, type: "visa"}
];

<script type="text/javascript">
// questions: For instance, how would I return the result set that matched results with a quantity more than 1, a total equal 90, a tip equal 0 and a type of tab? 
// create dimensions for each attribute
var payments_by_quantity = payments.dimension(function(d){return d.quantity});
     payments_by_total = payments.dimension(function(d){return d.total}),
     payments_by_tip = payments.dimension(function(d){return d.tip}),
     payments_by_type = payments.dimension(function(d){return d.type});
//need top(Infinity) to print out contents of filtered items
var morethan1 = payments_by_quantity.filter([1, Infinity]).top(Infinity);
console.log("morethan1",morethan1);
var tot_eq_90 = payments_by_total.filter(90).top(Infinity);
console.log("tot_eq_90",tot_eq_90);
// clear filters. If not, the result below will still be filtered by totals = 90
payments_by_total.filterAll();
console.log("top1= biggest paymt qty:", payments_by_quantity.top(1));
payments_by_total.filterAll();
console.log("top2= biggest paymt qty:", payments_by_quantity.top(2));
payments_by_total.filterAll();
console.log("bottom paymt tip:", payments_by_tip.bottom(1));
var tip_eq_0 = payments_by_tip.filter(0).top(Infinity);
console.log("tip_eq_0",tip_eq_0);
payments_by_total.filterAll();
var typetab = payments_by_type.filter("tab").top(Infinity);
console.log("typetab",typetab);
payments_by_total.filterAll();
var typetab_i = payments_by_type.top(Infinity);
console.log("typetab+i",typetab_i);
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