I have an attribute in CoreData which accepts a date value. I just want to get the current date and save it in this format "dd/mm/yyyy" . But don't know how. Thanks
If you're storing it as Date, then you have no control over the format until you try to present the returned value somewhere, and you just store Date()
If you're storing it as shown, then you need to use a DateFormatter to create the string you need
Here you can store date in coreData as shown in format
let date = NSDate()
var dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd/MM/yyyy"
var dateString = dateFormatter.string(from: date as Date)
store dateString in your coreData
To save dates in Core Data I have created the following extension
extension Date {
/**
Formats a Date
- parameters format: (String) for eg dd-MM-yyyy hh-mm-ss
*/
func format(format:String = "dd-MM-yyyy hh-mm-ss") -> Date {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = format
let dateString = dateFormatter.string(from: self)
if let newDate = dateFormatter.date(from: dateString) {
return newDate
} else {
return self
}
}
}
To set a date value of a field
let date = Date()
entity?.setValue(date.format(), forKey: "updated_at")
Note: You may see date saved as timestamp when you open your database. Please refer to the following issue NSDate being saved as timestamp in CoreData
You can also pass you own date formats in the "format()" extension to get different types of dates in the application
Related
I'm using this extension to convert a string containing date to Date() object:
extension String {
func toDate() -> Date?{
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd/MM/YYYY"
let date = dateFormatter.date(from: self)
return date
}
}
the result always containing a time in it. I'm curious where is the time coming from, why it is not all zero?
print("11/12/2021".toDate())
result is ->
2020-12-19 21:00:00 +0000
In the time that I run the code, it is showing 21:00:00, so why it is 21? I believe It is not related to my time because I run it at different times.
A Date object indicates an instant in time anywhere on the planet, independent of time zone.
A DateFormatter can convert a String to a Date (or a Date to a String, but ignore that for now). When it converts a String to a Date, it may make assumptions about the time of day if that is not included in the String. I believe it assumes that the time is midnight (00:00:00) in the date formatter's time zone. (And by the way, midnight is the starting point of a day, so midnight is zero hours/minutes/seconds into the day. Essentially midnight IS zeros for time.)
So when you call your String extension to convert "11/12/2021" to a Date, the extension creates a DateFormatter which defaults to the device time zone. It creates a Date assuming Midnight in the local time zone.
When you print that date, it gets displayed in GMT.
It looks like your format string has problems though. You're getting the wrong year and month. I think you must be using the wrong month or day string in your formatter. (I always have to look those up when I use them.)
Edit:
You likely want a format string of "MM-dd-yyyy"
(2-digit month, 2-digit day of month, and 4-digit year.)
Lower-case "m" or "mm" is minutes. Upper-case "Y" is for "week of year" based calendars, which you probably don't want.
Try this code:
func toDate() -> Date?{
let dateFormatter = DateFormatter()
let posixLocale = Locale(identifier: "en_US_POSIX")
dateFormatter.dateFormat = "MM-dd-yyyy"
dateFormatter.locale = posixLocale
let date = dateFormatter.date(from: self)
return date
}
}
And to use it:
let dateString = "12/11/2021"
let date = dateString.toDate()
print(date)
if let date = date {
let convertedDateString = DateFormatter.localizedString(from: date, dateStyle: .medium, timeStyle: .medium)
print(convertedDateString)
} else {
print("Can't convert \(dateString) to a date")
}
That displays "Dec 11, 2021 at 12:00:00 AM" in my US locale (US Date formatting.) Note that since I use the DateFormatter class method localizedString(from:dateStyle:timeStyle:) I see midnight as the displayed time (The time you get from a DateFormatter when you don't specify a time, but displayed in the local time zone.)
The answer is:
when we are converting a string to a Date Object the important part is the time zone that we are converting it to.
for example, if you convert your string date to a UTC time zone when you want to bring it back you have to set the time zone of the date to UTC.
let dateFormatter = DateFormatter()
dateFormatter.timeZone = TimeZone(identifier: "UTC")
so this is the reason why when we are printing the Date() object it is deferred from our string date.
extension String {
func toDate() -> Date?{
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "mm-dd-yyyy"
let date = dateFormatter.date(from: self)
return date
}
}
extension Date {
func toString() -> String {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "mm-dd-yyyy"
return dateFormatter.string(from: self)
}
}
let stringDate = "01-12-2021"
let date = "01-12-2021".toDate()
let convertBack = date?.toString()
print("(\(stringDate)) -> (\(date!)) -> (\(convertBack!))")
and the result is:
(01-12-2021) -> (2021-01-11 21:01:00 +0000) -> (01-12-2021)
so at the end when we convert back the Date object it will be the same. because that 2 dateFormatter in the extensions are using the default time zone. and if you want to specify a specific time zone you have to declare it in converting from and to string together.
// the creationdate is coming from an api call
var creationDate = "2020-11-04T16:46:59.439212Z"
let formatter = DateFormatter()
formatter.dateStyle = .long
formatter.timeStyle = .none
formatter.dateFormat = "dd-MM-yyyy"
var creationDateFormattedInToDate = formatter.date(from:
creationDate)
print("date \(creationDateFormattedInToDate)")
So i want that date in the format 04-11-2020 and pass in a UITextField.text
You will need two formatters, one to parse the input date to a Date object and one to convert the date object to a string of the right format.
The input date seems to be a variant of a internet date/time so we use a ISO8601DateFormatter
let formatter = ISO8601DateFormatter()
formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
The second formatter is a basic DateFormatter with a custom format
let outputFormatter = DateFormatter()
outputFormatter.dateFormat = "dd-MM-yyyy"
And then we can use them like this
if let date = formatter.date(from: creationDate) {
someTextField.text = outputFormatter.string(from: date)
}
You will want to use one formatter for parsing the response from the server (which is in what’s called and “ISO 8601” or “RFC 3339” format), and another for preparing the string representation of the date in the UI.
Regarding the date formatter for parsing the server response:
Set the formatter’s locale to Locale(identifier: "en_US_POSIX").
The setting of the styles when parsing this date string are irrelevant if you’re going to set dateFormat.
When parsing the date from the string, set dateFormat to yyyy-MM-dd'T'HH:mm:ss.SSSSSSX.
If you ever plan on using this formatter for the reverse date-to-string conversion (for preparing date strings to be sent to the server) you might want to set the timeZone of the formatter to TimeZone(secondsFromGMT: 0).
Regarding the date formatter used to prepare the string representation of the date in your UI:
I would not advise ever using a fixed dd-MM-yyyy format in your UI. That might be natural for European users, but it may be unnatural to most US users, who generally expect to see month before the day.
I would suggest not using dateFormat for this second date formatter, but rather using a dateStyle (e.g. of .medium or .long). It results in a nice, localized, and natural reading date string.
If you insist in using dd and MM and yyyy in your UI, I’d localize it with setLocalizedDateFormatFromTemplate so that the day and the month appear in the logical order that this particular user would expect (month-followed-by-day for US users, day-followed-by-month for most other locales).
Thus:
let serverDateFormatter = DateFormatter()
serverDateFormatter.locale = Locale(identifier: "en_US_POSIX")
serverDateFormatter.timeZone = TimeZone(secondsFromGMT: 0)
serverDateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSSSSX"
let uiFormatter = DateFormatter()
uiFormatter.dateStyle = .medium // or uiFormatter.setLocalizedDateFormatFromTemplate("ddMMyyyy")
if let date = serverDateFormatter.date(from: creationDateString) {
let string = uiFormatter.string(from: date)
// use that `string` in your UI
}
I am removing the current time from the current time and trying to find the minute difference. But it says 10/09/2019 13:13 and there is an error in the extraction process (I want to print as 1313) .1313 I can perform the extraction process. How do I print this data the way I want? I want to print dateFormat = "HHmm". In timertext2New.text, dateFormat = "dd / MM / yyyy HH: mm" like this. But I want to save it in HHmm format.
save12 output: 05/09/2019 10:48 but I want it to be "1048" . To perform extraction.
let formatter = DateFormatter()
formatter.dateFormat = "dd/MM/yyyy HH:mm"
timertext2New.text = formatter.string(from: datePicker.date)
let timehafıza2 = String(self.timertext2New.text!)
let df2 = DateFormatter()
df2.dateFormat = "HHmm"
var str2 = df2.string(from: Date())
str2 = timehafıza2
UserDefaults.standard.setValue(str2, forKey: "timertext2")
override func viewDidLoad() {
super.viewDidLoad()
let date = Date()
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HHmm"
let hour = dateFormatter.string(from: date)
var save12 = UserDefaults.standard.integer(forKey: "timertext2")
var fark : Int = (Int(hour)! - Int(save12))
}
Your code is pretty confusing and cannot work
You convert a date from a date picker with format "dd/MM/yyyy HH:mm"
Then you create a string with format "HHmm" from the current date which will be destroyed immediately because
You overwrite this string with the dd/MM/yyyy HH:mm string and save it to UserDefaults
Later you read the value from UserDefaults as integer which returns 0 because the "dd/MM/yyyy HH:mm" format is not representable by an integer.
My suggestion is to save all dates as Date and perform the date math with the dedicated methods of Calendar
I am trying to convert my string to a date using a static date formatter. When I make the call to stringToDate() using the variables below, a nil value is returned.
I've checked previous posts about this issue where people are saying it's because of the dateformatter locale or timeZone. However, that doesn't seem to be the issue in this case.
Does anyone know what the issue could be in this case? My code is below:
import Foundation
class DateHelper {
private static let dateFormatter: DateFormatter = {
let df = DateFormatter()
df.dateFormat = "yyyy-MM-dd hh:mm:ss"
df.locale = Locale(identifier: "en_GB")
df.timeZone = TimeZone.current
return df
}()
static func stringToDate(str: String, with dateFormat: String) -> Date? {
dateFormatter.dateFormat = dateFormat
let date = dateFormatter.date(from: str)
return date
}
}
var myDate = Date()
var dateStr = "2019-02-19T17:10:08+0000"
print(DateHelper.stringToDate(str: dateStr, with: "MMM d yyyy")) // prints nil
Looks like your string is in ISO8601 format. Use the ISO8601DateFormatter to get date instance. You can use ISO8601DateFormatter.Options to parse varieties of ISO8601 formats. For your string,
For Swift 4.2.1
let formatter = ISO8601DateFormatter()
let date = formatter.date(from: dateStr)
print(date!)
Should output
"2019-02-19 17:10:08 +0000\n"
Your date format doesn't match your input date. Try this code:
print(DateHelper.stringToDate(str: dateStr, with: "yyyy-MM-dd'T'HH:mm:ssZZZZZ"))
Hope this helps.
I want to get the date formate from the time stamp.so I am getting the timestamp is from the firebase database. so I am getting this output when it is retrieved from the firestore 2018-08-31T05:33:31.408Z . so I want to format the timestamp in the form "Aug 2018", 11.39 AM. so I tried to convert it with this code
let timestamp = deyaPaybalance.value(forKey: "timestamp") as! NSArray
print("timestamp is",timestamp)
//let len = timestamp.count
for element in timestamp {
let ele = element
let formatter = ISO8601DateFormatter()
//print("date is",date1!)
formatter.formatOptions = [.withFullDate,
.withTime,
.withDashSeparatorInDate,
.withColonSeparatorInTime]
let date2 = formatter.date(from: ele as! String)
print("timestamp with date is",date2!)
print("element is",ele)
}
But I am getting this type of output 2018-09-22 09:29:11 +0000 . So how to solve that one.
You are actually parsing the timestamp to a Date Object. Now if you want the date object to format any other way take a DateFormatter Variable, set dateFormat of the formatter and get the string from the date. That will convert the date to the expected string.
let anotherFormatter = DateFormatter()
anotherFormatter.dateFormat = "MMM yyyy, h:mm a"
anotherFormatter.string(from: date2)