迭代通過字典，直到兩種條件

Question

我有一個字典 - 列車（火車，列表（站）的） ... 站是具有兩個屬性布爾（station.src和station.dst）

類

我想重複詞典中循環，直到字典中的每一站都有這個兩個屬性等於真正

Do 
     li = New List(Of train)(trains.Keys) 
     For Each train In li 
      Dim s = trains(train).Item(1) 
      If s.name = sorc Then 
       s.src = True 
       s.dst = True 
       GoTo n1 
      End If 
      lo = New List(Of train)(trains.Keys) 
      For Each tr As train In lo 
       If s.name_t = trains(tr).Item(2).name_t Then 
        s.src = True 
        trains(tr).Item(2).dst = True 
        GoTo n1 
       End If 
      Next 
      trains.Remove(train) 
n1:   Next train 
     Loop Until (((each station.src in trains is true and each station.dst in trains is true)))) 

Answer 1

我有點什麼你的代碼是做丟失。我曾希望能夠稍微簡化它。如果你能解釋它背後的邏輯，那將是非常好的。

儘管如此，簡單的解決問題的方法是這樣的：

Loop Until trains.SelectMany(Function (kvp) kvp.Value).All(Function (s) s.src And s.dst) 

---

我很想知道這個代碼的接近程度給你結果你想：

Dim sorcs = _ 
    From kvp In trains 
    Where kvp.Value.Item(1).name = sorc 
    Select New With { .s1 = kvp.Value.Item(1), .s2 = kvp.Value.Item(2) } 

Dim pairs = _ 
    From kvp1 In trains 
    Join kvp2 In trains On kvp1.Value.Item(1).name_t Equals kvp2.Value.Item(2).name_t 
    Select New With { .s1 = kvp1.Value.Item(1), .s2 = kvp1.Value.Item(2) } 

For Each pair In sorcs.Concat(pairs) 
    pair.s1.src = True 
    pair.s2.dst = True 
Next