[英]Parsing arbitrary format JSON date with Swift Decodable
我正在嘗試將JSON文檔中的日期格式化為“ mm-dd-yyyy”格式。 我有以下數據:
{"data":[{
"id": 123,
"url": "https://www.google.com",
"title": "The Google link",
"created_at": "2017-08-29T04:00:00.000Z",//date to format
"sent": true,
"alternative": "https://google.com",
"things": [],
"description": [
"search",
"lookup"
],
"company": "Alphabet"
}]}
這是我的結構:
struct Sitedata: Decodable{
let data: [site]
}
struct site: Decodable {
let id: Int
let url: String
let title: String
let created_at: String
let sent: Bool
let alternative: String
let things: [String]
let description: [String]
let company: String
}
let sites = try JSONDecoder().decode(Sitedata.self, from: data)
我嘗試了以下方法,但結果為nil
:
func date(dateString: String){
// var dateString = "14.01.2017T14:54:00"
let format = "dd.MM.yyyy'T'HH:mm:ss"
let date = Date()
print("original String with date: \(dateString)")
print("date String() to Date(): \(dateString.toDate(format: format)!)")
print("date String() to formated date String(): \(dateString.toDateString(inputFormat: format, outputFormat: "dd MMMM")!)")
print("format Date(): \(date.toString(format: "dd MMM HH:mm")!)")
}
extension DateFormatter {
convenience init (format: String) {
self.init()
dateFormat = format
locale = Locale.current
}
}
extension String {
func toDate (format: String) -> Date? {
return DateFormatter(format: format).date(from: self)
}
func toDateString (inputFormat: String, outputFormat:String) -> String? {
if let date = toDate(format: inputFormat) {
return DateFormatter(format: outputFormat).string(from: date)
}
return nil
}
}
extension Date {
func toString (format:String) -> String? {
return DateFormatter(format: format).string(from: self)
}
}
How would I be able to parse and then format this date to MM-dd-yyyy?
首先,按照雨燕命名約定: UpperCamelCase
類名和lowerCamelCase
變量名。 其次,幫自己一個忙,並在Date
字段中創建created_at
,這很明顯。 以后您可以省下很多頭痛。
這是代碼:
struct SiteData: Decodable{
let data: [Site]
}
struct Site: Decodable {
let id: Int
let url: String
let title: String
let created_at: Date // changed to Date
let sent: Bool
let alternative: String
let things: [String]
let description: [String]
let company: String
}
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(formatter)
let sites = try decoder.decode(SiteData.self, from: json)
現在已經從JSON作為正確的Date
解析了created_at
,您可以根據需要設置其格式:
let formatter2 = DateFormatter()
formatter2.dateFormat = "MM-dd-yyyy"
print(formatter2.string(from: sites.data[0].created_at))
請注意, DateFormatter
創建成本非常高,更改其dateFormat
屬性的成本甚至更高。 如果必須將大量日期格式化為字符串(反之亦然),則只需創建一次日期格式化程序,然后繼續重復使用它們即可。
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