What is the correct date.format for MMM dd, yyyy hh:mm:ss a? and how convert to dd-mm-yyyy HH:ii

Question

I want convert this: Dec 31, 2017 8:00:00 PM to dd-mm-yyyy HH:ii format in Swift 4.

This is my code so far:

let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "MMM dd, yyyy hh:mm:ss a"//this your string date format

    if let translatedDate = dateFormatter.date(from: datetime) {
        dateFormatter.dateFormat = "dd-MM-yyyy HH:ii"
        return dateFormatter.string(from: translatedDate)
    }

The code never enters in the if statement. I guess my date format is not correct.

Theisen

It seems that translatedDate is nil, I tried in playground, no issue. So, an issue with local? Else, I don't the the ii in the format (unicode.org/reports/tr35/tr35-31/…), I don't know what you want to do with it, so if you pass the if let test, I don't think that dateFormatter.string(from: translatedDate) will be what you want. – Serviceman

Probably another "set dateFormatter.locale = Locale(identifier: "en_US_POSIX") " issue, compare #40692878 or #6613610 – but what does ii stand for? – Depravity

8 will not match hh, because hh expects two digits (so 08). Try a single h instead. – Doscher

your code is fine: let datetime = "Dec 31, 2017 8:00:00 PM" let dateFormatter = DateFormatter() dateFormatter.dateFormat = "MMM dd, yyyy hh:mm:ss a" dateFormatter.locale = Locale(identifier: "en_US_POSIX") if let translatedDate = dateFormatter.date(from: datetime) { dateFormatter.dateFormat = "dd-MM-yyyy HH:mm" let result = dateFormatter.string(from: translatedDate) print(result) // 31-12-2017 20:00 } anyway, I think ii is a mistake – Robot

@Cyrille: No, h matches any hour from 1 to 12. – Depravity

thanks @AndreaMugnaini . !!! – Theisen

Answer 1

A DateFormatter that converts between dates and their textual representations.

You can find more Locale identifier here.

• first, convert your date to local time zone. using a Locale class
• after you can covert the date in specific formate.

And try this code.

let dateStr = "Wed, 26 Jul 2017 18:10:02 +0530"
if let date = Date(fromString: dateStr, format: "MMM dd, yyyy hh:mm:ss a") {
        debugPrint(date.toString(format: "dd-MM-yyyy HH:ii"))
}

Date Extension is ...

extension Date {

    // Initializes Date from string and format
    public init?(fromString string: String, format: String, identifier: String = Locale.current.identifier) {
        let formatter = DateFormatter()
        formatter.dateFormat = format
        formatter.locale = Locale(identifier: identifier)
        if let date = formatter.date(from: string) {
            self = date
        } else {
            return nil
        }
    }

    // Converts Date to String, with format
    public func toString(format: String, identifier: String = Locale.current.identifier) -> String {
        let formatter = DateFormatter()
        formatter.locale = Locale(identifier: identifier)
        formatter.dateFormat = format
        return formatter.string(from: self)
    }
}

String Extension is ...

extension String {
    // Converts String to formated date string, with inputFormat and outputFormat
    public func toDate(form inputFormat: String, to outputFormat: String, identifier: String = Locale.current.identifier) -> String? {
        return Date(fromString: self, format: inputFormat, identifier: identifier)?.toString(format: outputFormat, identifier: identifier)
    }

    // Converts String to Date, with format
    func toDate(format: String, identifier: String = Locale.current.identifier) -> Date? {
        return Date(fromString: self, format: format, identifier: identifier)
    }
}

Rum

Force unwrapping the output of a dateformatter is a bad idea in a function which accepts the date format as an input argument. Either make your function throwable or return nil if either format is wrong. Moreover, if you are hardcoding the locale, set it to en_US_POSIX, not en_US. – Angelaangele