通過公共字段計算嵌套類中的重複對象

Question

我有一個對象數組，我想通過嵌套在每個對象內的公共屬性對它們進行分組。因爲我有麻煩去解釋它，我將發佈對象的類JSON表示：

reviewList: [{ // review object 
    userObject: {...} 
    content: [ 
     { 
      questionContent: "what sweets do you think John likes?", 
      questionId: 2, 
      answers: [{answer:"Candy"},{answer:"Chocolate"}] 
     }, 
     { 
      questionContent: "Do you like john?", 
      questionId: 3, 
      answers: [{answer:"No"}] 
     } 
    ] 
}, 
{ // review object 
    userObject: {...} 
    content: [ // Questions 
     { 
      questionContent: "what sweets do you think John likes?", 
      questionId: 2, 
      answers: [{answer:"Candy"}] 
     }, 
     { 
      questionContent: "Do you like john?", 
      questionId: 3, 
      answers: [{answer:"Yes"}] 
     } 
    ] 
}] 

我想從這個得到的是看起來很像下面的示例對象的列表：

[{ 
    content: 'what sweets do you think John likes?', 
    answers: [{content: "Candy", count: 2}, {content:"chocolate", count:1}] 
},{ 
    content: 'Do you like john?', 
    answers: [{content: "Yes", count: 1}, {content:"No", count:1}] 
}] 

到目前爲止，我已經嘗試了以下linq代碼，但我真的不知道如何繼續或如果我在正確的道路上。

reviewList 
    .SelectMany(x => x.Questions) 
    .GroupBy(x=>x.QuestionId) 
    .Select(x=>x 
     .ToLookup(y=>y.QuestionContent, y=>y.Answers.ToList()) 
    ) 

我也試圖與ToDictionary代替ToLookup，但我得到重複鍵異常

Answer 1

這是一個容易得多，如果你使用C＃的匿名對象，以顯示你的結構複製/粘貼。無論如何，您需要使用另一個SelectMany來合併答案：

var ans = reviewList.SelectMany(r => r.content).GroupBy(r => r.questionContent).Select(r => new { content = r.Key, answers = r.SelectMany(a => a.answers).GroupBy(a => a.answer).Select(a => new { content = a.Key, Count = a.Count() }) });