I have a DateFormatter that outputs the date in the format "2:00pm, Thu 18 Oct":
static func scheduleFormatter() -> DateFormatter {
let dateFormatter = DateFormatter()
dateFormatter.locale = Locale(identifier: "en_US_POSIX")
dateFormatter.amSymbol = "am"
dateFormatter.pmSymbol = "pm"
dateFormatter.dateFormat = "h:mma, EE dd MMM"
return dateFormatter
}
I need to add in the local time zone abbreviation of the user so that the string appears like "2:00 pm GMT, Thu 18 Oct". How can I do that?
Look at the Unicode Date Formatting Patterns:
Probably you want the pattern v:
The short generic non-location format. Where that is unavailable, falls back to the generic location format ("VVVV"), then the short localized GMT format as the final fallback.
or z:
The short specific non-location format. Where that is unavailable, falls back to the short localized GMT format ("O").
Note that time zone names are connected to language and setting posix locale will probably break that.
You could also ask for the abbreviation directly and include it in your format explicitly:
"h:mma, '\(TimeZone.current.abbreviation() ?? "")' EE dd MMM"
To display the time zone you can simply add "zzz" in your dateFormat string. For example: "h:mma zzz, EE dd MMM"
public static Date getCurrentTimeStampDate(){
String currentDate = new SimpleDateFormat(""yyyy:MM:dd HH:mm:ss").format(Calendar.getInstance(TimeZone.getTimeZone("GMT")).getTime());
SimpleDateFormat formater = new SimpleDateFormat(""yyyy:MM:dd HH:mm:ss");
try {
return formater.parse(currentDate);
} catch (ParseException e) {
return null;
}
}
Related
In our app there is the issue with creating a date from string but is only reproducible with a very specific combination. Unfortunately, there is no way of getting it from the user that experienced the issue, so I decided to just go for it and try every possible combination:
import Foundation
var dateOnlyDateFormatter: (String, String) -> DateFormatter = { timeZoneS, localeS in
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd"
formatter.timeZone = TimeZone(identifier: timeZoneS)
formatter.locale = Locale(identifier: localeS)
return formatter
}
let date = "2022-05-27"
let time = "06:15"
for timeZone in TimeZone.knownTimeZoneIdentifiers {
for locale in Locale.availableIdentifiers {
let dateFormatter = dateOnlyDateFormatter(timeZone, locale)
let printDate = dateFormatter.date(from: date)
if printDate == nil {
print("TimeZone: \(timeZone), Locale: \(locale)")
}
}
}
The result:
TimeZone: America/Asuncion, Locale: ar_SA
TimeZone: America/Asuncion, Locale: en_SA
I am not too sure what is the best way to handle this issue. Obviously our BE could return date using one specific Locale, like en_US_POSIX, but I have very little control over that, being a part of a much bigger older system. Has anybody experienced an issue like that?
If you read the "Working With Fixed Format Date Representations" section of the DateFormatter docs, you'll find:
For most fixed formats, you should also set the locale property to a POSIX locale ("en_US_POSIX"), and set the timeZone property to UTC.
You should probably just follow the advice here... But here's possibly why SA and the Paraguay timezone produces nil.
Further down that section, there is a link to a technical Q&A where this is explained in more detail. The part that is most related to your problem is:
A user can change their calendar (using System Preferences > Language & Region > Calendar on OS X, or Settings > General > International > Calendar on iOS). In that case NSDateFormatter will treat the numbers in the string you parse as if they were in the user's chosen calendar. For example, if the user selects the Buddhist calendar, parsing the year "2010" will yield an NSDate in 1467, because the year 2010 on the Buddhist calendar was the year 1467 on the (Gregorian) calendar that we use day-to-day.
In the locale SA, the numbers of your date string seem to be interpreted using the Islamic Calendar. Take a look at today's date when formatted with en_SA and America/New_York.
let dateFormatter = dateOnlyDateFormatter("America/New_York", "en_SA")
let printDate = dateFormatter.string(from: .init())
print(printDate)
// 1443-10-26
Also take a look at the non-nil dates that is parsed by en_SA and America/New_York
let dateFormatter = dateOnlyDateFormatter("America/New_York", "en_SA")
let printDate = dateFormatter.date(from: date)
print(printDate)
// 2583-10-05 04:00:00 +0000
Notice that 10-05 is the first Sunday of the year 2583 (See this calendar). If Paraguay still uses the same DST rules as it does now in 2583, then it would mean that there is a DST gap transition at 2583-10-05 00:00:00, starting the DST period. The hour starting from 00:00:00 would be skipped, so 00:00:00 would not exist.
When parsing a date only, DateFormatter would try to set the time components to be 00:00:00 in the timezone of the formatter, but 00:00:00 does not exist, so the parsing fails.
In any case, just set locale to posix and timeZone to UTC when you have set dateFormat.
So if you use 'time' like this, there will be no nil values:
let dateOnlyDateFormatter: (String, String) -> DateFormatter = { timeZoneS, localeS in
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd HH:mm"
formatter.timeZone = TimeZone(identifier: timeZoneS)
formatter.locale = Locale(identifier: localeS)
return formatter
}
let date = "2022-05-27 06:15"
//let time = "06:15"
for timeZone in TimeZone.knownTimeZoneIdentifiers {
for locale in Locale.availableIdentifiers {
let dateFormatter = dateOnlyDateFormatter(timeZone, locale)
let printDate = dateFormatter.date(from: date)
if printDate == nil {
print(">>>>>>>> TimeZone: \(timeZone), Locale: \(locale)")
} else {
print("..... \(printDate)")
}
}
}
I need to convert my date to string and then string to date. date is "2020-10-17 1:22:01 PM +0000"
Here is my date to string conversion code:
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssXXXXX"
let string = formatter.string(from: "2020-10-17 1:22:01 PM +0000")
let createdAT = string
its returning "2020-10-17 18:51:30+05:30"
Here is my string to date conversion code:
let dateFormatter = DateFormatter()
dateFormatter.locale = Locale(identifier: "en_US_POSIX")
dateFormatter.dateFormat = "yyyy-MM-dd' 'HH:mm:ssZ"
let date = dateFormatter.date(from:date)!
its returning "2020-10-17 1:21:30 PM +0000 - timeIntervalSinceReferenceDate : 624633690.0"
its returning the wrong date after i convert string to date. i need "2020-10-17 18:51:30+05:30" this time to be return when i convert string to 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.
I am struggling with Date and I'm assuming is TimeZone.
Currently I get from my backend a string like this "2020-04-07" and when I try to convert it to date it turns into 2020-04-06 22:00:00 +0000. I am in Spain (UTC+2) which I guess this is why it removes 2 hours?
This is my date formatter:
var dateFormatter: DateFormatter = {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
dateFormatter.timeZone = TimeZone.current
return dateFormatter
}()
And I call it dateFormatter.date(from: startDateString)
I am setting my current timezone but seems to be ignoring it or am I missing something?
I have followed a lot of answers from here but it's always the same result.
Thank you
The Date object does not have any inherent locale / time zone. It just represents a moment in time. If you want to see that Date as a string in a specific locale/time zone you have to use a date formatter. Or there's descriptionWithLocale. If you use print it will print a debug description of the Date instance in UTC.
This question already has answers here:
NSDateFormatter doesn't show time zone abbreviation for "Asia/Kolkata" for the "z" or "zzz" specifier, just the GMT offset
(1 answer)
What is the best way to deal with the NSDateFormatter locale "feature"?
(4 answers)
Closed 5 years ago.
I need to convert the following date string in to a Date in Swift 3.
Fri Dec 09 16:18:43 AMST 2016
Here is the code that i have been using, but it's getting cash on this particular date string conversion. (This date was logged on Android using new Date().toString() method.)
static func formatDate(date: String) -> String {
let dateFormatter = DateFormatter()
dateFormatter.timeZone = TimeZone(secondsFromGMT: 0)
dateFormatter.dateFormat = "EEE MMM dd HH:mm:ss zzz yyyy"
//Works for "Fri Sep 16 10:55:48 GMT+05:30 2016"
var myDate = dateFormatter.date(from: date)
// My date returns nil on "Fri Dec 09 16:18:43 AMST 2016"
dateFormatter.dateFormat = "dd/MM/yyyy"
return "\(dateFormatter.string(from: myDate!))"
}
There are both type of strings in the database. I tried with various types of Timezone formats (z/zz/zzz/zzzz/zzzzz) but always myDate returns nil.
Any help would be appreciated.
Thanks In Advance.
Apple doc for TimeZone(abbreviation:):
In general, you are discouraged from using abbreviations except for unique instances such as “GMT”. Time Zone abbreviations are not standardized and so a given abbreviation may have multiple meanings.
Does AMST represents "Amazon Summer Time" (UTC-3) or "Armenia Summer Time" (UTC+5)? See: https://www.timeanddate.com/time/zones
That's probably why it can't detect the proper timezone to use.
Solutions I can propose:
If you know which timezone AMST is:
replace AMST by UTC-3 or UTC+5 in the date string
remove AMST from the date string and use dateFormatter.timeZone = TimeZone(secondsFromGMT: -3 or 5 * 3600)
Have your source output a more precise timezone.
Note the following code, where AMST is understood correctly:
let df = DateFormatter()
df.locale = Locale.init(identifier: "pt_BR") // assuming AMST is Amazon Summer Time (UTC -3)
df.dateFormat = "HH:mm:ss z"
print(df.date(from: "16:18:43 AMST")) // Optional(2000-01-01 19:18:43 +0000)
But as soon as you include English day or month names (e.g. Fri or Dec) it will produce nil (because they aren't in Portuguese).
I've watching trough stack overflow to find the answer and I can't find it I want to cast this string value "1900-01-01T00:00:00" to Date format, I was trying with some formats like those:
"yyyy-MM-dd HH:mm:ss"
"EEE, dd MMM yyyy hh:mm:ss +zzzz"
"YYYY-MM-dd HH:mm:ss.A"
"yyyy-MM-dd HH:mm:ss.S"
but anyone of those its working.
and I want the date format like this
"dd-mm-yyyy"
Hope you can help me!
Thanks.
It is a two step process, first converting 1900-01-01T00:00:00 (known as a RFC 3999 or ISO 8601 date, referred to the specifications that define this format) into a Date object, and then converting that Date object back to a string in the form of 01-01-1900:
To convert your string in the form of 1900-01-01T00:00:00 into a Date object, you can use ISO8601DateFormatter:
let formatter = ISO8601DateFormatter()
formatter.formatOptions.remove(.withTimeZone)
let date = formatter.date(from: string)!
That is equivalent to the following DateFormat, in which one has to manually set the locale to en_US_POSIX (because RFC 3999/ISO 8601 dates use a Gregorian calendar, regardless of what the device's default calendar type) and sets the timeZone to GMT/Zulu, because usually RFC 3999/ISO 8601 dates are representing GMT unless specified otherwise:
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.timeZone = TimeZone(secondsFromGMT: 0)
let date = formatter.date(from: string)!
For more information about the importance of timezones and locales in parsing RFC 3999 and ISO 8601 dates, see Apple's Technical Q&A 1480.
Then, to convert that Date object to a string into 01-01-1900 (day, month, and year), you'd use a format string of dd-MM-yyyy (note the uppercase MM for "month", to distinguish it from mm for "minute"):
let formatter2 = DateFormatter()
formatter2.dateFormat = "dd-MM-yyyy"
let string = formatter2.string(from: date)
Two observations regarding the dateFormat string:
If this string is for displaying to the user, you might use use dateStyle rather than dateFormat, e.g.:
formatter2.dateStyle = .short
While this will generate a slightly different format, e.g. dd/MM/yy, the virtue of this approach is that the string will be localized (e.g. UK users will see MM/dd/yyyy, their preferred way of seeing short dates).
It just depends upon the purpose of your dd-MM-yyyy format. If it's for internal purposes, go ahead and use dateFormat. But if it's for showing dates in your UI, use dateStyle instead, and enjoy the localization that DateFormatter does automatically for you. For more information, see "Working With User-Visible Representations of Dates and Times" section of the DateFormatter reference.
Note that in the absence of a timeZone specified for this second formatter, it assumes that while the ISO 8601 date was in GMT, that you want to see the date in your local timezone. For example, (1900-01-01T00:00:00 GMT was Dec 31, 1899 at 4pm in California). If you want to see the date string of the original ISO 8601 object, not corrected for timezones, you'd just set the timeZone of this second formatter to be GMT as well, e.g.
formatter2.timeZone = TimeZone(secondsFromGMT: 0)
As others have pointed out, you want to avoid unnecessarily re-instantiating DateFormatter objects. So you might put these formatters in properties that are instantiated only once, or use an extension:
extension DateFormatter {
static let customInputFormatter: ISO8601DateFormatter = {
let formatter = ISO8601DateFormatter()
formatter.formatOptions.remove(.withTimeZone)
return formatter
}()
static let customOutputFormatter: DateFormatter = {
let formatter = DateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
formatter.timeZone = TimeZone(secondsFromGMT: 0) // if you want date in your local timezone, remove this line
return formatter
}()
}
And then:
let input = "1900-01-01T00:00:00"
let date = DateFormatter.customInputFormatter.date(from: input)!
let output = DateFormatter.customOutputFormatter.string(from: date)
print(output)
This is how I do custom date formatters:
extension DateFormatter {
static let inDateFormatter: DateFormatter = {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
return dateFormatter
}()
static let outDateFormatter: DateFormatter = {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd-mm-yyyy"
return dateFormatter
}()
}
And then use it like:
if let date = DateFormatter.inDateFormatter.date(from: "1900-01-01T00:00:00") {
let newDateString = DateFormatter.outDateFormatter.string(from: date);
print(newDateString) //prints 01-00-1900
}
This avoids any potential performance issues and is clear at the point of use, while still being concise.
Use this extension I created, where you can pass the format as a parameter.
extension String
{
func toDate( dateFormat format : String) -> Date
{
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = format
if let date = dateFormatter.date(from: self)
{
return date
}
print("Invalid arguments ! Returning Current Date . ")
return Date()
}
}
"1900-01-01T00:00:00".toDate(dateFormat: "yyyy-MM-dd'T'HH:mm:ss") //Plyground call test