Crossfilter尺寸过滤

Question

我正在研究dc.js图表​​。我已经安装了小提琴here。

我有下面的数据：

var data = [ 
    {"state": "A","value": 100,"volume": 10,"id": 4,"date": "10/1/2017","category": "H","channel": "CRM"}, 
    {"state": "B","value": 50,"volume": 10,"id": 2,"date": "8/1/2017","category": "A","channel": "CRM"}, 
    {"state": "A","value": 250,"volume": 5,"id": 4,"date": "10/1/2017","category": "H","channel": "CRM"}, 
    {"state": "A","value": 40,"volume": 4,"id": 3,"date": "9/1/2017","category": "A","channel": "Sales"}, 
    {"state": "C","value": 10,"volume": 1,"id": 5,"date": "11/1/2017","category": "A","channel": "Sales"}, 
    {"state": "B","value": 10,"volume": 1,"id": 2,"date": "8/1/2017","category": "H","channel": "CRM"}, 
    {"state": "D","value": 150,"volume": 3,"id": 1,"date": "7/1/2017","category": "A","channel": "Sales"}, 
    {"state": "D","value": 100,"volume": 5,"id": 1,"date": "7/1/2017","category": "H","channel": "Sales"}, 
    {"state": "C","value": 50,"volume": 1,"id": 5,"date": "11/1/2017","category": "H","channel": "Sales"} 
] 

我有四个维度（状态，类别，信道，ID）和所有通过值分组。

我需要知道，如果我可以过滤尺寸，使得如果我设置为60，图表应显示所有其值总是IDS大于60

例如它的状态饼图应仅显示值大于60的切片，即仅显示A和D.

Answer 1

本身，crossfilter不会过滤值。如果你仔细想想，在行减少之前，过滤由行减少到某个值的行的数据将会非常复杂。

但我认为你不是在寻找过滤，而只是没有显示太小的切片。你可以使用"fake group"来做到这一点。这是一个后处理步骤，不会更改交叉过滤器中包含的数据，只是您选择显示哪些项目。

这个与“删除空箱”假群组非常相似。但是不是查找值0，我们会查找最小值。

function remove_small_bins(source_group, lower_bound) { 
    return { 
     all:function() { 
      return source_group.all().filter(function(d) { 
       return d.value > lower_bound; 
      }); 
     } 
    }; 
} 

把它应用到你的榜样（小提琴数据从上述数据略有不同），我们首先需要看看d.value.orderValue instead of just d.value`：

function remove_small_bins(source_group, lower_bound) { 
    return { 
     all:function() { 
      return source_group.all().filter(function(d) { 
       return d.value.orderValue > lower_bound; 
      }); 
     } 
    }; 
} 

应用的假像组这样的：

var stateGroup = stateDim.group().reduce(reduceAdd, reduceRemove, reduceInitial); 
var stateGroupNoSmalls = remove_small_bins(stateGroup, 60); 
// ... 
stateChart 
    .group(stateGroupNoSmalls) 

叉的小提琴：https://jsfiddle.net/gordonwoodhull/cyjztajv/2/