C#中对象列表去重并聚合内部列表数据的实现问题

我有一个包含3条数据的对象列表，需要根据Property1、Property2以及InnerList中的Property3这三个条件判断对象是否匹配，匹配的话就累加对应Property3的Percentage数值。

原始数据 #

{
  "List": [
    {
      "Property1": "Apple",
      "Property2": "Fruit",
      "InnerList": [{"Property3": 100, "Percentage": 50.00}]
    },
    {
      "Property1": "Apple",
      "Property2": "Fruit",
      "InnerList": [{"Property3": 100, "Percentage": 50.00},
                   {"Property3": 50, "Percentage": 50.00}]
    },
    {
      "Property1": "Mango",
      "Property2": "Fruit",
      "InnerList": [{"Property3": 75, "Percentage": 50.00}]
    }
  ]
}

尝试过的代码 #

用Distinct()没效果，还写了一段LINQ查询，但不知道怎么给内部列表加条件，没得到期望结果：

var result = list
    .GroupBy(x=> new {x.Property1,x.Property2})
    .Select(grp => new Class
    {
        Property1 = grp.Key.Property1,
        Property2 = grp.Key.Property2,
        innerList = new List<InnerList>
        {
            new InnerList
            {
               Percentage = grp.SelectMany(x=> x.innerList).Sum(x=>x.Percentage)
            }
        }
    }).ToList();

期望结果 #

{
  "List": [
    {
      "Property1": "Apple",
      "Property2": "Fruit",
      "InnerList": [{"Property3": 100, "Percentage": 100.00},
                   {"Property3": 50, "Percentage": 50.00}]
    },
    {
      "Property1": "Mango",
      "Property2": "Fruit",
      "InnerList": [{"Property3": 75, "Percentage": 50.00}]
    }
  ]
}

解决方案 #

核心思路是先按外层的Property1和Property2分组，再在每个组内对InnerList按Property3分组累加Percentage，具体代码如下：

var result = list
    // 第一步：按外层的Property1和Property2分组，归拢同类型的外层对象
    .GroupBy(x => new { x.Property1, x.Property2 })
    .Select(grp => new Class
    {
        Property1 = grp.Key.Property1,
        Property2 = grp.Key.Property2,
        // 第二步：展开组内所有InnerList，按Property3分组后累加Percentage
        innerList = grp.SelectMany(x => x.innerList)
                       .GroupBy(inner => inner.Property3)
                       .Select(innerGrp => new InnerList
                       {
                           Property3 = innerGrp.Key,
                           Percentage = innerGrp.Sum(item => item.Percentage)
                       })
                       .ToList()
    })
    .ToList();

代码说明 #

1. 外层GroupBy把相同Property1和Property2的对象归为一组，比如两个Apple-Fruit的对象会被分到同一组
2. SelectMany把组内所有对象的InnerList展开成一个扁平列表，方便后续分组计算
3. 内层GroupBy按Property3分组，对每个分组内的Percentage求和，得到该Property3对应的总占比
4. 最后把聚合后的InnerList项收集起来，组装成符合要求的目标对象

内容的提问来源于stack exchange，提问作者Karthikeyan Sivakumar