Crossfilter尺寸過濾

Question

我正在研究dc.js圖表​​。我已經安裝了小提琴here。

我有下面的數據：

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"} 
] 

我有四個維度（狀態，類別，信道，ID）和所有通過值分組。

我需要知道，如果我可以過濾尺寸，使得如果我設置爲60，圖表應顯示所有其值總是IDS大於60

例如它的狀態餅圖應僅顯示值大於60的切片，即僅顯示A和D.

Answer 1

本身，crossfilter不會過濾值。如果你仔細想想，在行減少之前，過濾由行減少到某個值的行的數據將會非常複雜。

但我認爲你不是在尋找過濾，而只是沒有顯示太小的切片。你可以使用"fake group"來做到這一點。這是一個後處理步驟，不會更改交叉過濾器中包含的數據，只是您選擇顯示哪些項目。

這個與「刪除空箱」假羣組非常相似。但是不是查找值0，我們會查找最小值。

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

把它應用到你的榜樣（小提琴數據從上述數據略有不同），我們首先需要看看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; 
      }); 
     } 
    }; 
} 

應用的假像組這樣的：

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/