我想在我的swift项目中创建一个函数,将字符串转换为Dictionary json格式,但我得到了一个错误:
无法转换表达式的类型(@lvalue NSData,选项:整数可转换...
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中创建了这个函数:
- (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;
}
发布于 2015-05-27 19:11:11
警告:如果出于某些原因,您必须从JSON字符串进行操作,则这是一种将JSON字符串转换为字典的方便方法。但是,如果您有可用的JSON data,则应该改为使用,而不使用任何字符串。
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)
原创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,您没有将正确的参数传递给NSJSONSerialization
,并且忘记了转换结果。此外,最好检查可能的错误。最后一个注意事项:只有当你的值是一个字符串时,这个方法才有效。如果它可以是另一种类型,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,您还需要更改函数的返回类型:
func convertStringToDictionary(text: String) -> [String:AnyObject]? { ... }
发布于 2015-10-16 22:39:41
我已经更新了Swift 5的Eric D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
}
发布于 2016-12-24 01:39:30
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")
}
}
https://stackoverflow.com/questions/30480672
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