A Date formatter that converts between dates and their textual representations.
Date() –
var currentTime: Date = Date()
Date class always provides us UTC Time.
Default format of date object – 2020-07-13 15:09:57 +0000.
This date is UTC(Universal Time Coordinated) Prior to 1972, this time was called Greenwich Mean Time (GMT)
If you want to convert into Local Date use this method.
extension Date {
func toCurrentTimezone() -> Date {
let timeZoneDifference = TimeInterval(TimeZone.current.secondsFromGMT())
return self.addingTimeInterval(timeZoneDifference)
}
}
DateFormatter() –
let formatter = DateFormatter()
Instances of DateFormatter create string representations of Date objects, and convert textual representations of dates and times into Date objects. For user-visible representations of dates and times, DateFormatter provides a variety of localized presets and configuration options.
We take an example of Date Formatter –
“YYYY-MM-dd’T’HH:mm:ss“ – 2020–13–07T21:10:00
Looking at this, it would seem that the first part is the date (13th July, 2020) and the second part is the time (21:10:00, or 9:10pm in standard time).
After that, the “T” basically serves as a separator, saying “okay, we are transitioning to a time now” and the time is listed in a similar way as date, from large to small (hour:minute:second) with a colon separating each one.
Now we take some examples of DateFormatters –
Suppose we have date string. –
let input = “2020-13-10T21:29:00Z”
This is “yyyy-MM-dd’T’HH:mm:ssZ” format.
The ‘Z’ here refers to the time zone, and if the date
Time Zone –
| zzz | EST | The 3 letter name of the time zone. Falls back to GMT-08:00 (hour offset) if the name is not known. |
| zzzz | Eastern Standard Time | The expanded time zone name, falls back to GMT-08:00 (hour offset) if name is not known. |
| zzzz | CST-04:00 | Time zone with abbreviation and offset |
| Z | -0400 | RFC 822 GMT format. Can also match a literal Z for Zulu (UTC) time. |
| ZZZZZ | -04:00 | ISO 8601 time zone format |
Get Date from string with particulate format –
let input = “2020-13-10T21:29:00Z”
Let date = getDateFromString(strDate: input, requiredDateFormat: “yyyy-MM-dd’T’HH:mm:ss”)
func getDateFromString(strDate: String, requiredDateFormat : String) -> Date {
let dateFormatterGet = DateFormatter()
dateFormatterGet.timeZone = TimeZone(abbreviation: “UTC”)
dateFormatterGet.dateFormat = requiredDateFormat
return dateFormatterGet.date(from: strDate)!
}
Note: dateFormatterGet.timeZone = TimeZone(abbreviation: “UTC”) // It is necessary, owing to this, our date will not be impacted by timezone. If we don’t use this , DateFormatter class convert existing dateString to locale. (Whether it is already converted.)
Get String from Date for particulate format
func getStringFromDate(date: Date, requiredDateFormat : String) -> String {
let dateFormatterGet = DateFormatter()
dateFormatterGet.dateFormat = requiredDateFormat
dateFormatterGet.timeZone = TimeZone(abbreviation: “UTC”)
return dateFormatterGet.string(from: date)
}
Get String from Date for particulate format with local time zone.
static func getStringFromCurrentLocaleDate(date: Date, requiredDateFormat : String) -> String {
let dateFormatterGet = DateFormatter()
dateFormatterGet.dateFormat = requiredDateFormat
dateFormatterGet.locale = NSLocale.current
return dateFormatterGet.string(from: date)
}
Some other expended methods that convert date string from any format to required format-
func convertStringToDate(dateString:String, beforeformat : String, afterFormat : String) -> Date {
let dateFormatter = DateFormatter()
dateFormatter.timeZone = TimeZone(abbreviation: “UTC”)
dateFormatter.dateFormat = beforeformat
let newDate = dateFormatter.date(from: dateString)
dateFormatter.dateFormat = afterFormat
dateFormatter.timeZone = TimeZone.current
let newDateString = dateFormatter.string(from: newDate!)
dateFormatter.timeZone = TimeZone(abbreviation: “UTC”)
let date = dateFormatter.date(from: newDateString)
return date!
}
func convertStringToDateFormatString(dateString:String, beforeformat : String, afterFormat : String) -> String {
let dateFormatter = DateFormatter()
dateFormatter.timeZone = TimeZone(abbreviation: “UTC”)
dateFormatter.dateFormat = beforeformat
let newDate = dateFormatter.date(from: dateString)
let newDateFormatter = DateFormatter()
newDateFormatter.dateFormat = afterFormat
newDateFormatter.timeZone = TimeZone(abbreviation: “UTC”)
let newDateString = newDateFormatter.string(from: newDate!)
return newDateString
}
Other DateFomatter class in Swift 5 –
When working with date representations in ISO 8601 format, use ISO8601DateFormatter instead.
To represent an interval between two NSDate objects, use DateIntervalFormatter instead.
To represent a quantity of time specified by an NSDateComponents object, use DateComponentsFormatter instead.
You can get more information about ISO 8601
you can find more information at https://en.wikipedia.org/wiki/ISO_8601.
