无法转换表达式的类型(@lvalue NSData,options:IntegerLitralConvertible ...
这是我的代码:
func convertStringToDictionary (text:String) -> Dictionary<String,String> {
var data :NSData = text.dataUsingEncoding(NSUTF8StringEncoding)!
var json :Dictionary = NSJSONSerialization.JSONObjectWithData(data, options:0, error: nil)
return json
}
我在Objective-C中实现此功能:
- (NSDictionary*)convertStringToDictionary:(NSString*)string {
NSError* error;
//giving error as it takes dic, array,etc only. not custom object.
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
id json = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
return json;
}
#1 楼
警告:如果出于某种原因必须使用JSON字符串,这是将JSON字符串转换为字典的便捷方法。但是,如果有可用的JSON数据,则应改用数据,而不用一个字符串。Swift 3
func convertToDictionary(text: String) -> [String: Any]? {
if let data = text.data(using: .utf8) {
do {
return try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
} catch {
print(error.localizedDescription)
}
}
return nil
}
let str = "{\"name\":\"James\"}"
let dict = convertToDictionary(text: str)
Swift 2
func convertStringToDictionary(text: String) -> [String:AnyObject]? {
if let data = text.dataUsingEncoding(NSUTF8StringEncoding) {
do {
return try NSJSONSerialization.JSONObjectWithData(data, options: []) as? [String:AnyObject]
} catch let error as NSError {
print(error)
}
}
return nil
}
let str = "{\"name\":\"James\"}"
let result = convertStringToDictionary(str)
原始Swift 1答案:
func convertStringToDictionary(text: String) -> [String:String]? {
if let data = text.dataUsingEncoding(NSUTF8StringEncoding) {
var error: NSError?
let json = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.allZeros, error: &error) as? [String:String]
if error != nil {
println(error)
}
return json
}
return nil
}
let str = "{\"name\":\"James\"}"
let result = convertStringToDictionary(str) // ["name": "James"]
if let name = result?["name"] { // The `?` is here because our `convertStringToDictionary` function returns an Optional
println(name) // "James"
}
在您的版本中,您没有将适当的参数传递给
NSJSONSerialization
并忘记转换结果。另外,最好检查可能的错误。最后说明:仅当您的值为字符串时,此方法才有效。如果它可能是另一种类型,则最好像这样声明字典转换:let json = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.allZeros, error: &error) as? [String:AnyObject]
,当然,您还需要更改该类型的返回类型。功能:
func convertStringToDictionary(text: String) -> [String:AnyObject]? { ... }
#2 楼
我已经更新了Eric D对于Swift 5的答案: func convertStringToDictionary(text: String) -> [String:AnyObject]? {
if let data = text.data(using: .utf8) {
do {
let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String:AnyObject]
return json
} catch {
print("Something went wrong")
}
}
return nil
}
评论
本示例返回nil。 let x =“ {\” a \“:[\” b \“:\” B \“,\” c \“:\” C \“]}” let结果= convertStringToDictionary(x)
–赛义德·塔里克(Syed Tariq)
16年7月21日在20:06
#3 楼
Swift 3:if let data = text.data(using: String.Encoding.utf8) {
do {
let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String:Any]
print(json)
} catch {
print("Something went wrong")
}
}
#4 楼
在Swift 3中,JSONSerialization
具有称为jsonObject(with:options:)
的方法。 jsonObject(with:options:)
具有以下声明:class func jsonObject(with data: Data, options opt: JSONSerialization.ReadingOptions = []) throws -> Any
从给定的JSON数据返回Foundation对象。
使用
jsonObject(with:options:)
,您必须处理错误处理(try
,try?
或try!
)并键入强制转换(来自Any
)。因此,您可以使用以下一种模式来解决您的问题。#1。使用抛出并返回非可选类型的方法
import Foundation
func convertToDictionary(from text: String) throws -> [String: String] {
guard let data = text.data(using: .utf8) else { return [:] }
let anyResult: Any = try JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String] ?? [:]
}
用法:
let string1 = "{\"City\":\"Paris\"}"
do {
let dictionary = try convertToDictionary(from: string1)
print(dictionary) // prints: ["City": "Paris"]
} catch {
print(error)
}
let string2 = "{\"Quantity\":100}"
do {
let dictionary = try convertToDictionary(from: string2)
print(dictionary) // prints [:]
} catch {
print(error)
}
let string3 = "{\"Object\"}"
do {
let dictionary = try convertToDictionary(from: string3)
print(dictionary)
} catch {
print(error) // prints: Error Domain=NSCocoaErrorDomain Code=3840 "No value for key in object around character 9." UserInfo={NSDebugDescription=No value for key in object around character 9.}
}
#2。使用引发并返回可选类型的方法
import Foundation
func convertToDictionary(from text: String) throws -> [String: String]? {
guard let data = text.data(using: .utf8) else { return [:] }
let anyResult: Any = try JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String]
}
let string1 = "{\"City\":\"Paris\"}"
do {
let dictionary = try convertToDictionary(from: string1)
print(String(describing: dictionary)) // prints: Optional(["City": "Paris"])
} catch {
print(error)
}
let string2 = "{\"Quantity\":100}"
do {
let dictionary = try convertToDictionary(from: string2)
print(String(describing: dictionary)) // prints nil
} catch {
print(error)
}
let string3 = "{\"Object\"}"
do {
let dictionary = try convertToDictionary(from: string3)
print(String(describing: dictionary))
} catch {
print(error) // prints: Error Domain=NSCocoaErrorDomain Code=3840 "No value for key in object around character 9." UserInfo={NSDebugDescription=No value for key in object around character 9.}
}
#3。使用不会抛出并返回非可选类型的方法
import Foundation
func convertToDictionary(from text: String) -> [String: String] {
guard let data = text.data(using: .utf8) else { return [:] }
let anyResult: Any? = try? JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String] ?? [:]
}
用法:
let string1 = "{\"City\":\"Paris\"}"
let dictionary1 = convertToDictionary(from: string1)
print(dictionary1) // prints: ["City": "Paris"]
let string2 = "{\"Quantity\":100}"
let dictionary2 = convertToDictionary(from: string2)
print(dictionary2) // prints: [:]
let string3 = "{\"Object\"}"
let dictionary3 = convertToDictionary(from: string3)
print(dictionary3) // prints: [:]
#4。使用不会抛出并返回可选类型的方法
import Foundation
func convertToDictionary(from text: String) -> [String: String]? {
guard let data = text.data(using: .utf8) else { return nil }
let anyResult = try? JSONSerialization.jsonObject(with: data, options: [])
return anyResult as? [String: String]
}
let string1 = "{\"City\":\"Paris\"}"
let dictionary1 = convertToDictionary(from: string1)
print(String(describing: dictionary1)) // prints: Optional(["City": "Paris"])
let string2 = "{\"Quantity\":100}"
let dictionary2 = convertToDictionary(from: string2)
print(String(describing: dictionary2)) // prints: nil
let string3 = "{\"Object\"}"
let dictionary3 = convertToDictionary(from: string3)
print(String(describing: dictionary3)) // prints: nil
#5 楼
Swift 4extension String {
func convertToDictionary() -> [String: Any]? {
if let data = self.data(using: .utf8) {
do {
return try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
} catch {
print(error.localizedDescription)
}
}
return nil
}
}
评论
只是另一个复制粘贴
– J. Doe
18-09-13在11:47
如果您不使用选项,则不要编写它们:JSONSerialization.jsonObject(with:data)
– Zaporozhchenko Oleksandr
19年1月10日在15:27
#6 楼
雨燕5extension String {
func convertToDictionary() -> [String: Any]? {
if let data = data(using: .utf8) {
return try? JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
}
return nil
}
}
#7 楼
我找到了将json字符串转换为NSDictionary或NSArray的代码。只需添加扩展名。SWIFT 3.0
如何使用
let jsonData = (convertedJsonString as! String).parseJSONString
/>
extension String
{
var parseJSONString: AnyObject?
{
let data = self.data(using: String.Encoding.utf8, allowLossyConversion: false)
if let jsonData = data
{
// Will return an object or nil if JSON decoding fails
do
{
let message = try JSONSerialization.jsonObject(with: jsonData, options:.mutableContainers)
if let jsonResult = message as? NSMutableArray {
return jsonResult //Will return the json array output
} else if let jsonResult = message as? NSMutableDictionary {
return jsonResult //Will return the json dictionary output
} else {
return nil
}
}
catch let error as NSError
{
print("An error occurred: \(error)")
return nil
}
}
else
{
// Lossless conversion of the string was not possible
return nil
}
}
}
评论
根本不要在Swift中使用NSMutable ...集合类型。将类型强制转换为NSMutable ...将永远不会导致可变对象。在Swift 3+中,未指定的类型是Any,而不是AnyObject。
–vadian
18年8月30日在12:12
#8 楼
详细信息Xcode版本10.3(10G8),Swift 5
解决方案
import Foundation
// MARK: - CastingError
struct CastingError: Error {
let fromType: Any.Type
let toType: Any.Type
init<FromType, ToType>(fromType: FromType.Type, toType: ToType.Type) {
self.fromType = fromType
self.toType = toType
}
}
extension CastingError: LocalizedError {
var localizedDescription: String { return "Can not cast from \(fromType) to \(toType)" }
}
extension CastingError: CustomStringConvertible { var description: String { return localizedDescription } }
// MARK: - Data cast extensions
extension Data {
func toDictionary(options: JSONSerialization.ReadingOptions = []) throws -> [String: Any] {
return try to(type: [String: Any].self, options: options)
}
func to<T>(type: T.Type, options: JSONSerialization.ReadingOptions = []) throws -> T {
guard let result = try JSONSerialization.jsonObject(with: self, options: options) as? T else {
throw CastingError(fromType: type, toType: T.self)
}
return result
}
}
// MARK: - String cast extensions
extension String {
func asJSON<T>(to type: T.Type, using encoding: String.Encoding = .utf8) throws -> T {
guard let data = data(using: encoding) else { throw CastingError(fromType: type, toType: T.self) }
return try data.to(type: T.self)
}
func asJSONToDictionary(using encoding: String.Encoding = .utf8) throws -> [String: Any] {
return try asJSON(to: [String: Any].self, using: encoding)
}
}
// MARK: - Dictionary cast extensions
extension Dictionary {
func toData(options: JSONSerialization.WritingOptions = []) throws -> Data {
return try JSONSerialization.data(withJSONObject: self, options: options)
}
}
用法
let value1 = try? data.toDictionary()
let value2 = try? data.to(type: [String: Any].self)
let value3 = try? data.to(type: [String: String].self)
let value4 = try? string.asJSONToDictionary()
let value5 = try? string.asJSON(to: [String: String].self)
测试样本
不要忘记在此处粘贴解决方案代码
func testDescriber(text: String, value: Any) {
print("\n//////////////////////////////////////////")
print("-- \(text)\n\n type: \(type(of: value))\n value: \(value)")
}
let json1: [String: Any] = ["key1" : 1, "key2": true, "key3" : ["a": 1, "b": 2], "key4": [1,2,3]]
var jsonData = try? json1.toData()
testDescriber(text: "Sample test of func toDictionary()", value: json1)
if let data = jsonData {
print(" Result: \(String(describing: try? data.toDictionary()))")
}
testDescriber(text: "Sample test of func to<T>() -> [String: Any]", value: json1)
if let data = jsonData {
print(" Result: \(String(describing: try? data.to(type: [String: Any].self)))")
}
testDescriber(text: "Sample test of func to<T>() -> [String] with cast error", value: json1)
if let data = jsonData {
do {
print(" Result: \(String(describing: try data.to(type: [String].self)))")
} catch {
print(" ERROR: \(error)")
}
}
let array = [1,4,5,6]
testDescriber(text: "Sample test of func to<T>() -> [Int]", value: array)
if let data = try? JSONSerialization.data(withJSONObject: array) {
print(" Result: \(String(describing: try? data.to(type: [Int].self)))")
}
let json2 = ["key1": "a", "key2": "b"]
testDescriber(text: "Sample test of func to<T>() -> [String: String]", value: json2)
if let data = try? JSONSerialization.data(withJSONObject: json2) {
print(" Result: \(String(describing: try? data.to(type: [String: String].self)))")
}
let jsonString = "{\"key1\": \"a\", \"key2\": \"b\"}"
testDescriber(text: "Sample test of func to<T>() -> [String: String]", value: jsonString)
print(" Result: \(String(describing: try? jsonString.asJSON(to: [String: String].self)))")
testDescriber(text: "Sample test of func to<T>() -> [String: String]", value: jsonString)
print(" Result: \(String(describing: try? jsonString.asJSONToDictionary()))")
let wrongJsonString = "{\"key1\": \"a\", \"key2\":}"
testDescriber(text: "Sample test of func to<T>() -> [String: String] with JSONSerialization error", value: jsonString)
do {
let json = try wrongJsonString.asJSON(to: [String: String].self)
print(" Result: \(String(describing: json))")
} catch {
print(" ERROR: \(error)")
}
测试日志
//////////////////////////////////////////
-- Sample test of func toDictionary()
type: Dictionary<String, Any>
value: ["key4": [1, 2, 3], "key2": true, "key3": ["a": 1, "b": 2], "key1": 1]
Result: Optional(["key4": <__NSArrayI 0x600002a35380>(
1,
2,
3
)
, "key2": 1, "key3": {
a = 1;
b = 2;
}, "key1": 1])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: Any]
type: Dictionary<String, Any>
value: ["key4": [1, 2, 3], "key2": true, "key3": ["a": 1, "b": 2], "key1": 1]
Result: Optional(["key4": <__NSArrayI 0x600002a254d0>(
1,
2,
3
)
, "key2": 1, "key1": 1, "key3": {
a = 1;
b = 2;
}])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String] with cast error
type: Dictionary<String, Any>
value: ["key4": [1, 2, 3], "key2": true, "key3": ["a": 1, "b": 2], "key1": 1]
ERROR: Can not cast from Array<String> to Array<String>
//////////////////////////////////////////
-- Sample test of func to<T>() -> [Int]
type: Array<Int>
value: [1, 4, 5, 6]
Result: Optional([1, 4, 5, 6])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String]
type: Dictionary<String, String>
value: ["key1": "a", "key2": "b"]
Result: Optional(["key1": "a", "key2": "b"])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String]
type: String
value: {"key1": "a", "key2": "b"}
Result: Optional(["key1": "a", "key2": "b"])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String]
type: String
value: {"key1": "a", "key2": "b"}
Result: Optional(["key1": a, "key2": b])
//////////////////////////////////////////
-- Sample test of func to<T>() -> [String: String] with JSONSerialization error
type: String
value: {"key1": "a", "key2": "b"}
ERROR: Error Domain=NSCocoaErrorDomain Code=3840 "Invalid value around character 21." UserInfo={NSDebugDescription=Invalid value around character 21.}
#9 楼
为了快速5,我编写了一个演示进行验证。extension String {
/// convert JsonString to Dictionary
func convertJsonStringToDictionary() -> [String: Any]? {
if let data = data(using: .utf8) {
return (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String: Any]
}
return nil
}
}
let str = "{\"name\":\"zgpeace\"}"
let dict = str.convertJsonStringToDictionary()
print("string > \(str)")
// string > {"name":"zgpeace"}
print("dicionary > \(String(describing: dict))")
// dicionary > Optional(["name": zgpeace])
#10 楼
let JSONData = jsonString.data(using: .utf8)!
let jsonResult = try JSONSerialization.jsonObject(with: data, options: .mutableLeaves)
guard let userDictionary = jsonResult as? Dictionary<String, AnyObject> else {
throw NSError()}
评论
您想要字典中的值和ket是什么?我更新我的问题... @ Amit89无关紧要什么是价值和关键!!!
@ Amit89我想要将文本赋予函数时返回json字典格式
让jsonDictionary =试试JSONSerialization.jsonObject(with:jsonData,options:[])as! [String:String];