我有一个 JSON,我需要它将它转换为对象数组。这是我的 JSON(它的简短版本)
[
{
"categoryID": 5,
"categoryDescription": "Trips",
"groupID": 43,
"groupDescription": "USA",
"groupImage": "e613c87a-4dab-4929-90cf-2b584fdf0399.jpg",
"subgroupDescription": "2 days",
"subgroupPrice": "200"
},
{
"categoryID": 5,
"categoryDescription": "Trips",
"groupID": 43,
"groupDescription": "USA",
"groupImage": "e613c87a-4dab-4929-90cf-2b584fdf0399.jpg",
"subgroupDescription": "5 days",
"subgroupPrice": "500"
},
{
"categoryID": 5,
"categoryDescription": "Trips",
"groupID": 33,
"groupDescription": "Mexico",
"groupImage": "e613c87a-4dab-4929-90cf-2b584fdf0399.jpg",
"subgroupDescription": "3 days",
"subgroupPrice": "400"
},
{
"categoryID": 5,
"categoryDescription": "Trips",
"groupID": 33,
"groupDescription": "Mexico",
"groupImage": "e613c87a-4dab-4929-90cf-2b584fdf0399.jpg",
"subgroupDescription": "1 days",
"subgroupPrice": "150"
},
{
"categoryID": 3,
"categoryDescription": "Hotels",
"groupID": 22,
"groupDescription": "My Hotel",
"groupImage": "e613c87a-4dab-4929-90cf-2b584fdf0399.jpg",
"subgroupDescription": "1 night",
"subgroupPrice": "50"
},
{
"categoryID": 3,
"categoryDescription": "Hotels",
"groupID": 10,
"groupDescription": "Your Hotel",
"groupImage": "e613c87a-4dab-4929-90cf-2b584fdf0399.jpg",
"subgroupDescription": "2 nights",
"subgroupPrice": "150"
}]
我需要制作一个这样的自定义对象:(我如何在 Swift 4 中创建这样的对象?)
在 JSON 中,我们有categoryID和groupID,我需要根据它们过滤数组,例如,我只需要一个 categoryID 为 5 的对象。我只需要一个 groupID 为 43 的对象。但我需要所有子组。这是我的对象的结构:(我不知道我是否在正确的道路上)
struct Categories {
var categoryID: NSNumber
var categoryDescription: String
var groups : [Groups]}
struct Groups {
var geoupID: NSNumber
var geoupDescription: String
var groupImage: String
var subGroups : [Subgroups] }
struct Subgroups {
var subgroupPrice: NSNumber
var subgroupDescription: String }
我怎样才能以最好的方式过滤它?
至于如何制作结构,只需使用Decodable
并根据您在 JSON 中期望的内容命名字段,或者使用CodingKeys
来指定名称。例如:
struct MyStruct: Decodable {
let categoryID: Int
let categoryDescription: String
let groupID: Int
// …
}
然后,您可以将结果解码为[MyStruct]
使用JSONDecoder
.
现在,真正的问题似乎是您希望在内部拥有与您收到的 JSON 不同的结构,包括诸如“每个中只有一个categoryID
”之类的约束。可能最直接的方法是迭代解码结果并将内容复制到不同的结构中。
代替数组(例如,var groups: [Groups]
),您可以使用带有groupID
as 键的字典来强制每个 id 只有一个,例如:
guard let results = try? jsonDecoder.decode([MyStruct].self, from: json) else { return }
var categories = [Int: Category]()
for result in results {
// fetch existing category or make a new one
var category = categories[result.categoryID, default: Category(id: result.categoryID, description: result.categoryDescription)]
// fetch existing group in category or make a new one
var group = category.groups[result.groupID, default: Group(id: result.groupID, description: result.groupDescription, image: result.groupImage)]
// append subgroup (always new since there is no id)
let subgroup = Subgroup(description: result.subgroupDescription, price: result.subgroupPrice)
group.subgroups.append(subgroup)
// "save"
category.groups[result.groupID] = group
categories[result.categoryID] = category
}
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