從NSDictionary/Dictionary中刪除所有項目，其中值== -1.0

Question

我正在將數據從1格式遷移到另一個格式，以便對我的iOS應用程序之一進行大型更新。這意味着當用戶更新他們的應用程序時，它將他們的數據遷移到新的位置。這個新的地點有更嚴格的規則，並使用適當的做法（基本上，當我第一次創建應用程序，我是一個noob，目前在數據庫中有不好的做法，這個新的位置僅用於良好的數據）。

我有一切都很好地遷移，一切正常，除了我需要做最後一件事。我保存到數據庫的大型字典（它使用firebase fyi）在任何地方存儲-1.0應該有一個零值（我知道是壞的）。我需要做的是遍歷整個字典並刪除鍵值爲-1.0的任何鍵。

字典的類型是[AnyHashable：Any]，這是Firebase使用的類型。

到目前爲止，我已經嘗試過。

if let data = dataDictionary as? [AnyHashable : Any] { 

    let foundItems = data.filter { $0.value as? Double == -1.0 } 

    print(foundItems) 
} 

該計劃然後遍歷該找到的項目數組，並從包含它的數據字典中刪除任何鍵。

這是數據字典的樣子：

"-KpIdh_TQMG4fyfFgkdt" =     { 
       assignments =      { 
        "-KpIgH6uN19OpcuedYe1" =       { 
         assignmentGoal = "-1"; 
         assignmentName = "Information System Proposal"; 
         assignmentResult = 100; 
         assignmentWeight = 5; 
        }; 
        "-KpIgJnFlC6fhgS0NWxF" =       { 
         assignmentGoal = "-1"; 
         assignmentName = "Information System"; 
         assignmentResult = "-1"; 
         assignmentWeight = 35; 
        }; 
        "-KpIgOGSAwg_VSpDWhWR" =       { 
         assignmentGoal = "-1"; 
         assignmentName = "Process Analysis"; 
         assignmentResult = "-1"; 
         assignmentWeight = 30; 
        }; 
        "-KpIgPhu_3Zxw36xt3O4" =       { 
         assignmentGoal = "-1"; 
         assignmentName = Labs; 
         assignmentResult = "-1"; 
         assignmentWeight = 10; 
        }; 
        "-KpIgQoFEdRnLlMAq2VN" =       { 
         assignmentGoal = "-1"; 
         assignmentName = Exam; 
         assignmentResult = "-1"; 
         assignmentWeight = 20; 
        }; 
       }; 
       paperColor = 22; 
       paperGoal = 95; 
       paperName = "Systems Analysis"; 
      }; 
     }; 
     semesterCode = 17S2; 
     semesterGoal = 90; 
     semesterName = "2017 Semester Two"; 
    }; 
}; 

，這是它應該是什麼樣子

"-KpIdh_TQMG4fyfFgkdt" =     { 
       assignments =      { 
        "-KpIgH6uN19OpcuedYe1" =       { 
         assignmentName = "Information System Proposal"; 
         assignmentResult = 100; 
         assignmentWeight = 5; 
        }; 
        "-KpIgJnFlC6fhgS0NWxF" =       { 
         assignmentName = "Information System"; 
         assignmentWeight = 35; 
        }; 
        "-KpIgOGSAwg_VSpDWhWR" =       { 
         assignmentName = "Process Analysis"; 
         assignmentWeight = 30; 
        }; 
        "-KpIgPhu_3Zxw36xt3O4" =       { 
         assignmentName = Labs; 
         assignmentWeight = 10; 
        }; 
        "-KpIgQoFEdRnLlMAq2VN" =       { 
         assignmentName = Exam; 
         assignmentWeight = 20; 
        }; 
       }; 
       paperColor = 22; 
       paperGoal = 95; 
       paperName = "Systems Analysis"; 
      }; 
     }; 
     semesterCode = 17S2; 
     semesterGoal = 90; 
     semesterName = "2017 Semester Two"; 
    }; 
}; 

Answer 1

的解決方案，我已經是映射（迭代）在每個父鍵和將它的子節點分配給一個變量孩子。然後測試每個子屬性（賦值Goal，賦值名等）爲「-1」爲字符串，-1爲整數。如果匹配，則從子女中刪除該鍵：值對。

然後將孩子分配回父節點。

let result: [Any] = dict.map { dictionary in 
    var d = dictionary 
    var child = d.value as Dictionary 

    if let goal = child["assignmentGoal"] as? String, goal == "-1" { 
     child.removeValue(forKey: "assignmentGoal") 
    } 

    if let name = child["assignmentName"] as? String, name == "-1" { 
     child.removeValue(forKey: "assignmentName") 
    } 

    if let result = child["assignmentResult"] as? Int, result == -1 { 
     child.removeValue(forKey: "assignmentResult") 
    } 

    if let weight = child["assignmentWeight"] as? Int, weight == -1 { 
     child.removeValue(forKey: "assignmentWeight") 
    } 

    d.value = child 

    return d 
} 

//show the output 
for item in result { 
    print(item) 
} 

和結果輸出

(key: "-KpIgOGSAwg_VSpDWhWR", 
    value: ["assignmentName": "Process Analysis System", "assignmentWeight": 30]) 
(key: "-KpIgQoFEdRnLlMAq2VN", 
    value: ["assignmentName": "Exam", "assignmentWeight": 20]) 
(key: "-KpIgJnFlC6fhgS0NWxF", 
    value: ["assignmentName": "Information System", "assignmentGoal": "3", "assignmentWeight": 35]) 
(key: "-KpIgPhu_3Zxw36xt3O4", 
    value: ["assignmentName": "Labs", "assignmentWeight": 10]) 
(key: "-KpIgH6uN19OpcuedYe1", 
    value: ["assignmentName": "Information System Proposal", "assignmentResult": 100, "assignmentWeight": 5])