How to Convert This Date Format in Swift

How to convert date format from dd/MM/YYYY to YYYY-MM-dd in swift

First changes your year formatter with yyyy and instead of using two NSDateFormatter use just one like this

let inputFormatter = NSDateFormatter()
inputFormatter.dateFormat = "MM/dd/yyyy"
let showDate = inputFormatter.dateFromString("07/21/2016")
inputFormatter.dateFormat = "yyyy-MM-dd"
let resultString = inputFormatter.stringFromDate(showDate!)
print(resultString)

For Swift3 and later

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MM/dd/yyyy"
let date = dateFormatter.date(from: date)
dateFormatter.dateFormat = "yyyy-MM-dd"
let resultString = dateFormatter.string(from: date!)
print(resultString)

How to convert string date time format to another format using Swift

extension String {
func convertToDateFormate(current: String, convertTo: String) -> String {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = current
    guard let date = dateFormatter.date(from: self) else {
        return self
    }
    dateFormatter.dateFormat = convertTo
    return  dateFormatter.string(from: date)
}
}

convert to required formate as

let dateString = "12-10-2019"
let convertedDate = dateString.convertToDateFormate(current: "dd-MM-YYYY", convertTo: "YYYY-MM-dd")

Swift date format returning wrong date

The code in your question is muddled up. You try to convert a string into a string in the first example and something unspecified into a Date in the second example.

Here's how to convert a Date into a String:

import Foundation

let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssXXXXX"
let string: String = formatter.string(from: Date())

print(string) // prints for example 2020-10-18T10:54:07+01:00

Here's how to convert a string into a date

let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "yyyy-MM-dd' 'HH:mm:ssZ"
let date: Date = formatter.date(from: "2020-10-18 10:59:56+0100")! // In real life, handle the optional properly
print(date)  // prints 2020-10-18 09:59:56 +0000

When you print a Date directly, it automatically uses UTC as the time zone. This is why it changed it in the code above.

In the examples, I explicitly specified the type of string and date to show what type they are. Type inference means you can omit these in normal code.

As a general rule when handling dates:

• always use Date in your code. Date is a type that stores the number of seconds since Jan 1st 1970 UTC.
• Only convert dates to strings when displaying them to the user or communicating with an external system.
• When calculating periods etc, always use a Calendar to get things like date components and intervals in units other than seconds. You might think to get "the same time tomorrow" you could just add 24 * 60 * 60 to a Date but in many countries, like mine, that will work on only 363 days in the year. Calendar will correctly handle things like daylight saving and leap years.

Date Format in Swift

You have to declare 2 different NSDateFormatters, the first to convert the string to a NSDate and the second to print the date in your format.

Try this code:

let dateFormatterGet = NSDateFormatter()
dateFormatterGet.dateFormat = "yyyy-MM-dd HH:mm:ss"

let dateFormatterPrint = NSDateFormatter()
dateFormatterPrint.dateFormat = "MMM dd,yyyy"

let date: NSDate? = dateFormatterGet.dateFromString("2016-02-29 12:24:26")
print(dateFormatterPrint.stringFromDate(date!))

Swift 3 and higher:

From Swift 3 NSDate class has been changed to Date and NSDateFormatter to DateFormatter.

let dateFormatterGet = DateFormatter()
dateFormatterGet.dateFormat = "yyyy-MM-dd HH:mm:ss"

let dateFormatterPrint = DateFormatter()
dateFormatterPrint.dateFormat = "MMM dd,yyyy"

if let date = dateFormatterGet.date(from: "2016-02-29 12:24:26") {
    print(dateFormatterPrint.string(from: date))
} else {
   print("There was an error decoding the string")
}

Can't Convert Date Format Into Display Date In Swift

You should always set your dateFormat locale to "en_US_POSIX" before setting the dateFormat. Btw it looks like that your date string you are reading from database is always in UTC format, if that is the case you should set your dateFormatter timezone to zero secondsFromGMT and escape your date string timezone:

let dateFormatter = DateFormatter()
dateFormatter.locale = Locale(identifier: "en_US_POSSIX")
dateFormatter.dateFormat = "EEE MMM dd yyyy HH:mm:ss 'GMT+0000 (Greenwich Mean Time)'"
dateFormatter.timeZone = TimeZone(secondsFromGMT: 0)
dateFormatter.date(from: "Thu Nov 12 2020 07:00:00 GMT+0000 (Greenwich Mean Time)")

---

You should also create a static date formatter to avoid creating a new one every time you call this method:

---

extension Formatter {
    static let customDate: DateFormatter = {
        let dateFormatter = DateFormatter()
        dateFormatter.locale = Locale(identifier: "en_US_POSSIX")
        dateFormatter.dateFormat = "EEE MMM dd yyyy HH:mm:ss 'GMT+0000 (Greenwich Mean Time)'"
        dateFormatter.timeZone = TimeZone(secondsFromGMT: 0)
        return dateFormatter
    }()
    static let yyyyMMMd: DateFormatter = {
        let dateFormatter = DateFormatter()
        dateFormatter.setLocalizedDateFormatFromTemplate("yyyyMMMd")
        return dateFormatter
    }()
}

---

extension String {
    func convertToDate() -> Date? {
        Formatter.customDate.date(from: self)
    }
    func convertToDisplayFormat() -> String {
        convertToDate()?.convertToMonthDayTimeFormat() ?? "N/A"
    }
}

---

extension Date {
    func convertToMonthDayTimeFormat() -> String {
        Formatter.yyyyMMMd.string(from: self)
    }
}

---

Playground testing:

"Thu Nov 12 2020 07:00:00 GMT+0000 (Greenwich Mean Time)".convertToDisplayFormat()  // "Nov 12, 2020"

How to change date format from dd MMMM YYYY in swift?

Using DateFormatter is right way to do. First you need to convert the 01 August 2021 , String type, to Date object. Second, change dateFormat and re-format it. Here is tested code for both of your need:

func convert(_ dateString: String, from initialFormat: String, to targetFormat: String? = nil, _ locale: Locale? = nil) -> String? {
    let formatter = DateFormatter()
    formatter.dateFormat = initialFormat
    guard let date = formatter.date(from: dateString) else { return nil }
    
    if let newFormat = targetFormat {
        formatter.dateFormat = targetFormat
    }
    formatter.locale = locale
    return formatter.string(from: date)
}

print(convert("01 August 2021", from: "dd MMMM yyyy", .init(identifier: "id_ID")))
print(convert("01 August 2021", from: "dd MMMM yyyy", to: "dd-MM-yyyy"))

Swift Convert Date to Date with dateFormat

Answer to your question: No.

You can create a date/string extension, that can solve your problem in one-line. Note, Date object is a date object. It does not have any format (like string).

May this help you:

extension String {

    func convertDateString() -> String? {
        return convert(dateString: self, fromDateFormat: "yyyy-MM-dd'T'HH:mm:ssZ", toDateFormat: "yyyy-MM-dd")
    }

    func convert(dateString: String, fromDateFormat: String, toDateFormat: String) -> String? {

        let fromDateFormatter = DateFormatter()
        fromDateFormatter.dateFormat = fromDateFormat

        if let fromDateObject = fromDateFormatter.date(from: dateString) {

            let toDateFormatter = DateFormatter()
            toDateFormatter.dateFormat = toDateFormat

            let newDateString = toDateFormatter.string(from: fromDateObject)
            return newDateString
        }

        return nil
    }

}

Use one-line code:

let newDateString = "my date string".convertDateString()

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