[英]parsing nested Array using codable in swift 4
我收到許多隨機問題。 大多像某些結構無法解碼,無法理解如何定義結構。
請發現代碼被截斷
var JSON = """
{"variants":{"variant_groups":[{"group_id":"1","name":"Crust","variations":[{"name":"Thin","price":0,"default":1,"id":"1","inStock":1},{"name":"Thick","price":0,"default":0,"id":"2","inStock":1,"isVeg":1},{"name":"Cheese burst","price":100,"default":0,"id":"3","inStock":1,"isVeg":1}]},{"group_id":"2","name":"Size","variations":[{"name":"Small","price":0,"default":1,"id":"10","inStock":1,"isVeg":0},{"name":"Medium","price":100,"default":0,"id":"11","inStock":1,"isVeg":1},{"name":":Large","price":200,"default":0,"id":"12","inStock":1,"isVeg":0}]},{"group_id":"3","name":"Sauce","variations":[{"name":"Manchurian","price":20,"default":0,"id":"20","inStock":1,"isVeg":0},{"name":"Tomato","price":20,"default":0,"id":"21","inStock":1,"isVeg":1},{"name":"Mustard","price":20,"default":0,"id":"22","inStock":1,"isVeg":0}]}],"exclude_list":[[{"group_id":"1","variation_id":"3"},{"group_id":"2","variation_id":"10"}],[{"group_id":"2","variation_id":"10"},{"group_id":"3","variation_id":"22"}]]}}
""".data(using: .utf8)
/*
not sure is this the right way to define Root
*/
struct Root : Codable {
let variants : varientStruct
let exclude_list : exclude_list
}
struct exclude_list : Codable{
let variation_id : String
let group_id : String
}
struct varientStruct: Codable {
let variant_groups = [variant_groups_struct]
}
struct variant_groups_struct : Codable {
let group_id : String
let name :String
let variations: [variationsStruct]
}
struct variationsStruct :Codable {
let name : String
let price : Int
let selected: Int
let id : String
let inStock: Bool
enum CodingKeys : String, CodingKey {
case name
case price
case selected = "default"
case id
case inStock
}
}
}
do {
let data = Data(person.utf8)
let result = try JSONDecoder().decode(Root.self, from: JSON)
print(result)
} catch {
print(error)
}
首先,請再次遵守命名約定:
struct
名和class
名以大寫字母開頭。 struct
/ class
名都是駝峰式的,而不是snake_cased的 。 其次,JSON非常易於閱讀。 只有兩種集合類型(數組[]
和字典{}
)和四種值類型。
格式化JSON字符串以便能夠更方便地識別結構
let jsonString = """
{"variants":{"variant_groups":[{"group_id":"1","name":"Crust","variations":
[{"name":"Thin","price":0,"default":1,"id":"1","inStock":1},
{"name":"Thick","price":0,"default":0,"id":"2","inStock":1,"isVeg":1},
{"name":"Cheese burst","price":100,"default":0,"id":"3","inStock":1,"isVeg":1}]
},{"group_id":"2","name":"Size","variations":
[{"name":"Small","price":0,"default":1,"id":"10","inStock":1,"isVeg":0},
{"name":"Medium","price":100,"default":0,"id":"11","inStock":1,"isVeg":1},
{"name":":Large","price":200,"default":0,"id":"12","inStock":1,"isVeg":0}]
},{"group_id":"3","name":"Sauce","variations":
[{"name":"Manchurian","price":20,"default":0,"id":"20","inStock":1,"isVeg":0},
{"name":"Tomato","price":20,"default":0,"id":"21","inStock":1,"isVeg":1},
{"name":"Mustard","price":20,"default":0,"id":"22","inStock":1,"isVeg":0}]
}],
"exclude_list":[[{"group_id":"1","variation_id":"3"}, {"group_id":"2","variation_id":"10"}],
[{"group_id":"2","variation_id":"10"},{"group_id":"3","variation_id":"22"}]]
}
}
"""
然后根據JSON結構逐步構建結構
struct Root : Decodable {
let variants : Variant
}
struct Variant : Decodable {
private enum CodingKeys : String, CodingKey {
case groups = "variant_groups"
case excludeList = "exclude_list"
}
let groups : [VariantGroup]
let excludeList : [[ExcludeList]]
}
struct VariantGroup : Decodable {
private enum CodingKeys : String, CodingKey {
case groupID = "group_id"
case name, variations
}
let groupID : String
let name : String
let variations : [Variation]
}
struct Variation : Decodable {
let name : String
let price : Int
let `default` : Int
let id : String
let inStock : Int
}
struct ExcludeList : Decodable {
private enum CodingKeys : String, CodingKey {
case groupID = "group_id"
case variationID = "variation_id"
}
let groupID : String
let variationID : String
}
然后解碼東西
do {
let data = Data(jsonString.utf8)
let result = try JSONDecoder().decode(Root.self, from: data)
print(result)
} catch { print(error) }
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