Question

这是我的json：

[
  {
    "category" : {
      "id" : 1,
      "text" : "cat1"
    },
    "id" : 1,
    "title" : "book1"
  },{
    "category" : {
      "id" : 2,
      "text" : "cat2"
    },
    "id" : 2,
    "title" : "book2"
  },{
    "category" : {
      "id" : 1,
      "text" : "cat1"
    },
    "id" : 3,
    "title" : "book3"
  }
]

如何按类别分组？我想在不同的 collectionView

中使用它们

提前谢谢

Answer 1

如下定义您的JSON可编码类。

typealias Result = [ResultElement]

struct ResultElement: Codable {
    let category: Category
    let id: Int
    let title: String
}

struct Category: Codable {
    let id: Int
    let text: String
}

现在，在使用JSONDecoder进行JSON解析之后，对Result数组进行迭代，并通过等号运算符比较Category结构并将其分组。由于默认情况下，类别结构中的Int和String符合Equatable协议，因此也可以使用Equatable协议来比较类别结构。

Answer 2

您可以尝试

        let str = """
[
{
"category" : {
"id" : 1,
"text" : "cat1"
},
"id" : 1,
"title" : "book1"
},{
"category" : {
"id" : 2,
"text" : "cat2"
},
"id" : 2,
"title" : "book2"
},{
"category" : {
"id" : 1,
"text" : "cat1"
},
"id" : 3,
"title" : "book3"
}
]


"""

        do {

            let res = try JSONDecoder().decode([Root].self, from: Data(str.utf8))

            print(res)

            let dic = Dictionary(grouping: res, by: { $0.category.text})

            print(dic) // this dictionary is your new data source key is title of section value is sections rows 
        }
        catch {
            print(error)
        }

struct Root: Codable {
    let category: Category
    let id: Int
    let title: String
}

struct Category: Codable {
    let id: Int
    let text: String
}

Answer 3

创建结构

//MARK: - MyData
public struct MyData {

    public var category : Category
    public var id : Int
    public var title : String

}

//MARK: - Category
public struct Category {

    public var id : Int
    public var text : String

}

创建模型

func createData () -> [MyData] {
    let c1 = Category.init(id: 1, text: "Cat1")
    let d1 = MyData.init(category: c1, id: 1, title: "Book1")
    let c2 = Category.init(id: 2, text: "Cat2")
    let d2 = MyData.init(category: c2, id: 2, title: "Book2")
    let c3 = Category.init(id: 1, text: "Cat1")
    let d3 = MyData.init(category: c3, id: 3, title: "Book3")

    return [d1, d2, d3]

}

对数据进行分组

    let ungroupedData = createData()
    print("Ungrouped\n")
    print(ungroupedData)
    let groupedData = Dictionary(grouping: ungroupedData, by: {$0.category.text})
    print("\nGrouped\n")
    print(groupedData)

    groupedData["Cat1"] // get cat1 array list

分组JSON内容

3 个答案: