如何使用带有动态键的Swift 4从嵌套JSON中提取数据
我有一个JSON数据结构,使用上传时创建的唯一键。如果我逐行阅读字典中的每一项,我就能阅读所有的内容。然而,我正试图修改我的代码以使用Swift 4可编码属性 不幸的是,读这些书并没有把我推到天才的地位 JSON类似于以下简单示例: 请注意,诸如“123”、“456”、“case1”、“case2”、“u1”、“u2”等键在运行时是未知的如何使用带有动态键的Swift 4从嵌套JSON中提取数据,json,swift4,Json,Swift4,我有一个JSON数据结构,使用上传时创建的唯一键。如果我逐行阅读字典中的每一项,我就能阅读所有的内容。然而,我正试图修改我的代码以使用Swift 4可编码属性 不幸的是,读这些书并没有把我推到天才的地位 JSON类似于以下简单示例: 请注意,诸如“123”、“456”、“case1”、“case2”、“u1”、“u2”等键在运行时是未知的 let json = """ { "things" : { "123" : { "name" : "Pa
let json = """
{
"things" : {
"123" : {
"name" : "Party",
"owner" : "Bob",
"isActive" : true,
"cases" : {
"case1" : {
"no" : 1
},
"case2" : {
"no" : 2
}
}
},
"456" : {
"name" : "Bus",
"owner" : "Joe",
"isActive" : true
}
},
"users" : {
"u1" : {
"name" : "Summer"
},
"u2" : {
"name" : "Daffy"
}
}
}
"""
接下来,我能够为大部分数据创建解码器,但不能为嵌套字典创建解码器(在本例中,cases的作用类似于嵌套字典)。我确信我遗漏了一些简单的东西
如果我试图包含注释掉的部分,操场将不会运行,不会给出错误
struct Thing: Decodable {
let id: String
let isActive: Bool
let name: String
let owner: String
//var cases = [Case]()
init(id: String, isActive: Bool, name: String, owner: String){//}, cases: [Case]?) {
self.id = id
self.isActive = isActive
self.name = name
self.owner = owner
//self.cases = cases ?? [Case(id: "none", caseNumber: 0)]
}
}
struct User: Decodable {
let id: String
let name: String
}
struct Case: Decodable {
let id: String
let caseNumber: Int
}
struct ResponseData: Decodable {
var things = [Thing]()
var users = [User]()
enum CodingKeys: String, CodingKey {
case trips
case users
}
private struct PhantomKeys: CodingKey {
var intValue: Int?
var stringValue: String
init?(intValue: Int) { self.intValue = intValue; self.stringValue = "\(intValue)" }
init?(stringValue: String) { self.stringValue = stringValue }
}
private enum ThingKeys: String, CodingKey {
case isActive, name, owner, cases
}
private enum UserKeys: String, CodingKey {
case name
}
private enum CaseKeys: String, CodingKey {
case id
case caseNumber = "no"
}
init(from decoder: Decoder) throws {
let outer = try decoder.container(keyedBy: CodingKeys.self)
let thingcontainer = try outer.nestedContainer(keyedBy: PhantomKeys.self, forKey: .things)
for key in thingcontainer.allKeys {
let aux = try thingcontainer.nestedContainer(keyedBy: ThingKeys.self, forKey: key)
let name = try aux.decode(String.self, forKey: .name)
let owner = try aux.decode(String.self, forKey: .owner)
let isActive = try aux.decode(Bool.self, forKey: .isActive)
// let c = try aux.nestedContainer(keyedBy: CaseKeys.self, forKey: .cases)
// var cases = [Case]()
// for ckey in c.allKeys {
// let caseNumber = try c.decode(Int.self, forKey: .caseNumber)
// let thiscase = Case(id: ckey.stringValue, caseNumber: caseNumber)
// cases.append(thiscase)
// }
let thing = Thing(id: key.stringValue, isActive: isActive, name: name, owner: owner)//, cases: cases)
things.append(thing)
}
let usercontainer = try outer.nestedContainer(keyedBy: PhantomKeys.self, forKey: .users)
for key in usercontainer.allKeys {
let aux = try usercontainer.nestedContainer(keyedBy: UserKeys.self, forKey: key)
let name = try aux.decode(String.self, forKey: .name)
let user = User(id: key.stringValue,name: name)
users.append(user)
}
}
}
它适用于事物和用户,但我必须忽略这些情况。请参见注释//中的打印输出
let data = json.data(using: .utf8)!
let things = try JSONDecoder().decode(ResponseData.self, from: data).things
print(things[0])
//Thing(id: "456", isActive: true, name: "Bus", owner: "Joe")
let users = try JSONDecoder().decode(ResponseData.self, from: data).users
print(users[0])
//User(id: "u1", name: "Summer")
我曾尝试使用对我来说似乎更干净的指南,但我没有成功地实施它
这个代码是
我的问题有两个:
您可以尝试以下方法:
let data = jsonData.data(using: .utf8)
let json = try JSONSerialization.jsonObject(with: data!) as! [String:Any]
let things = json["things"] as! [String:Any]
for (thing_key, thing_value) in things as [String:Any] {
let thing = thing_value as! [String:Any]
if let cases = thing["cases"] as? [String:Any]{
for (case_key, case_value) in cases {
print(case_key)
print(case_value)
}
}
}
编辑
我最初不理解你的问题,这里是你的代码改进,以获得案件。这是一个快速的工作,所以可能不是最佳的,但你得到的想法:
struct Thing: Decodable {
let id: String
let isActive: Bool
let name: String
let owner: String
var cases: [Case]?
init(id: String, isActive: Bool, name: String, owner: String , cases: [Case]?) {
self.id = id
self.isActive = isActive
self.name = name
self.owner = owner
self.cases = cases
}
}
struct User: Decodable {
let id: String
let name: String
}
struct Case: Decodable {
let id: String
let caseNumber: Int
}
struct ResponseData: Decodable {
var things = [Thing]()
var users = [User]()
enum CodingKeys: String, CodingKey {
case things
case users
case cases
}
private struct PhantomKeys: CodingKey {
var intValue: Int?
var stringValue: String
init?(intValue: Int) { self.intValue = intValue; self.stringValue = "\(intValue)" }
init?(stringValue: String) { self.stringValue = stringValue }
}
private enum ThingKeys: String, CodingKey {
case isActive, name, owner, cases
}
private enum UserKeys: String, CodingKey {
case name
}
private enum CaseKeys: String, CodingKey {
case no
}
init(from decoder: Decoder) throws {
let outer = try decoder.container(keyedBy: CodingKeys.self)
let thingcontainer = try outer.nestedContainer(keyedBy: PhantomKeys.self, forKey: .things)
for key in thingcontainer.allKeys {
let aux = try thingcontainer.nestedContainer(keyedBy: ThingKeys.self, forKey: key)
let name = try aux.decode(String.self, forKey: .name)
let owner = try aux.decode(String.self, forKey: .owner)
let isActive = try aux.decode(Bool.self, forKey: .isActive)
var cases:[Case]? = []
do{
let casescontainer = try aux.nestedContainer(keyedBy: PhantomKeys.self, forKey: .cases)
for case_key in casescontainer.allKeys{
let caseaux = try casescontainer.nestedContainer(keyedBy: CaseKeys.self, forKey: case_key)
let no = try caseaux.decode(Int.self, forKey: .no)
let thingCase = Case(id:case_key.stringValue, caseNumber: no)
cases?.append(thingCase)
}
}catch{ }
let thing = Thing(id: key.stringValue, isActive: isActive, name: name, owner: owner , cases: cases)
things.append(thing)
}
let usercontainer = try outer.nestedContainer(keyedBy: PhantomKeys.self, forKey: .users)
for key in usercontainer.allKeys {
let aux = try usercontainer.nestedContainer(keyedBy: UserKeys.self, forKey: key)
let name = try aux.decode(String.self, forKey: .name)
let user = User(id: key.stringValue,name: name)
users.append(user)
}
}
}
这将产生以下输出:
let data = json.data(using: .utf8)!
let things = try JSONDecoder().decode(ResponseData.self, from: data).things
print("-----")
for thing in things{
print(thing)
}
print("---")
let users = try JSONDecoder().decode(ResponseData.self, from: data).users
for user in users{
print(user)
}
您可以通过以下方式从当前json获取密钥:
jq -r 'keys[]'
在通过检索到的每个密钥在循环中进行查询之后您无法通过协议在Swift中自动编码/解码动态密钥的值–此类工作需要手动完成。我可以使用动态密钥执行此操作-见上文。“123”和“456”是动态键,我在获取数据时不知道。它通过“幻影键”工作——我想我是手动操作的。然而,我仍然无法理解嵌套的“案例”,我认为这是不可能的。请看我下面的答案,我重用了你的“幻影键”在你的“东西”中创建了一个可选的案例列表-我最初理解错了你的问题,因此编辑,我将原始响应留在那里只是为了参考或是为了百万次编辑,我花了一段时间才到达那里:)哦,天哪。当然,我需要再次使用幻影密钥,因为案例与对象和用户一样具有未知ID。谢谢你解决了这个问题@mike_t。你能在swift中使用
jq
吗?
jq -r 'keys[]'