Question

我需要将所有键及其类的值转换为小写。例如，

class Person : Encodable {
    var firstName: String
    var lastName: String
     var city: String
}

 var person = Person(firstName: "David", lastName: "Gill", city: 
 "Toronto")
 let encoder = JSONEncoder()
 encoder.keyEncodingStrategy = .convertToLowerCase
 let encoded = try encoder.encode(person)
 print(String(decoding: encoded, as: UTF8.self))

convertToLowerCase是我在JSONEncoder.KeyEncodingStrategy扩展名中添加的一种用于将密钥转换为小写字母的方法。

它打印-{"city":"Toronto","firstname":"David","lastname":"Gill"}

我需要打印的是-{"city":"toronto","firstname":"david","lastname":"gill"}

有人可以在这里帮忙吗？

Answer 1

赞：

struct Person : Codable {
    var firstName: String
    var lastName: String
    var city: String
    enum CodingKeys : String, CodingKey {
        case firstName = "firstname"
        case lastName = "lastname"
        case city
    }
    func encode(to encoder: Encoder) throws {
        var con = encoder.container(keyedBy: CodingKeys.self)
        try! con.encode(self.firstName.lowercased(), forKey: .firstName)
        try! con.encode(self.lastName.lowercased(), forKey: .lastName)
        try! con.encode(self.city.lowercased(), forKey: .city)
    }
}

测试：

let person = Person(firstName: "David", lastName: "Gill", city:
    "Toronto")
let encoder = JSONEncoder()
let encoded = try encoder.encode(person)
print(String(decoding: encoded, as: UTF8.self))
// {"firstname":"david","lastname":"gill","city":"toronto"}

您可能可以合并.convertToLowerCase来保存一些工作。

Answer 2

您可以先转换每个值：

var firstName = "David"
var lastName = "Gill"
var city = "Toronto"

var editedFirst = firstName.lowercased()
var editedLast = lastName.lowercased()
var editedCity = city.lowercased()

 var person = Person(firstName: editedFirst, lastName: editedLast, city: 
 editedCity)

 let encoder = JSONEncoder()
 encoder.keyEncodingStrategy = .convertToLowerCase
 let encoded = try encoder.encode(person)
 print(String(decoding: encoded, as: UTF8.self))

它不能让您一次性转换整个对象的属性，但可以将您的值与键一起转换。

关于您是否可以为类中的每个属性进行遍历的问题：如何将每个属性的LowerCased版本添加到类中？

类似的东西：

class Person : Encodable {
    var firstName: String
    var lastName: String
     var city: String

  let editedFirst = firstName.lowercased()
  let editedLast = lastName.lowercased()
  let editedCity = city.lowercased()
}

然后您可以在需要时访问该小写的值。

Answer 3

这不是一个完美的答案，但是输入评论太长了。

但这是我会尝试的：

将您的对象转换为字典（带有类似https://stackoverflow.com/a/46049763/503527的东西）
将字典值映射为小写（这对于映射字典值https://stackoverflow.com/a/24219069/503527是一个很好的答案）
一旦有了映射的字典，就可以使用JSONencode，并且应该拥有所需的内容。

强制将所有属性键和swift类的值转换为小写

3 个答案: