跳過當添加「讓」元素不能lambda表達式

Question

內進行計數，我有以下lambda表達式：

string queryToken = queryTokens.Last(); 
var result = from locationAddress in locations 
      let tokens = GetLetterTokens(locationAddress.Name) 
      let distance = (from token in tokens 
          where token.Contains(queryToken, StringComparison.OrdinalIgnoreCase) 
          select token.Length - queryToken.Length).Min() 
      orderby distance 
      select new 
         { 
          LocationAddress = locationAddress, 
          LocationDistance = distance, 
         }; 

這不要緊，它是寫的。有時在計算distance時，沒有tokens包含queryToken，因此無法返回.Min()。如何跳過這些情況？我不想將它們添加到result變量中。

Answer 1

聽起來像是你只是想：

let tokens = ... 
where tokens.Any(token.Contains(queryToken, StringComparison.OrdinalIgnoreCase)) 
let distance = ... 

另外，當您選擇令牌只是過濾，然後檢查是否任何存在：

var result = from locationAddress in locations 
      let tokens = GetLetterTokens(locationAddress.Name) 
           .Where(token => token.Contains(queryToken, StringComparison.OrdinalIgnoreCase) 
      where tokens.Any() 
      let distance = tokens.Min(token => token.Length - queryToken.Length)