Datefromstring() Returns Incorrect Date

dateFromString() returns incorrect date

The format for year is incorrect, it should be yyyy, not YYYY.

"Y": Year (in "Week of Year" based calendars). This year designation is used in ISO year-week calendar as defined by ISO 8601, but can be used in non-Gregorian based calendar systems where week date processing is desired. May not always be the same value as calendar year.

See: Date Field SymbolTable.

Also: ICU Formatting Dates and Times

NSDateFormatter dateFromString returns incorrect date

I don't believe that Dhruv's answer is correct. In fact, it's not clear there's any problem at all. You just seem to have an incorrect expectation of what should happen and/or interpretation of what's happening.

NSDate represents a moment in time. This moment does not have one unique name. It will be known by different names in different places and under different naming systems (time zones, calendars). NSDate doesn't deal with any of this, except lamely in its -description method, where it has to produce a string representation of that moment.

Second, a string like "02-06-2012" doesn't specify a precise moment in time. First of all, it's just a date with no time information, so NSDateFormatter just defaults to the first moment for that date. Second, it doesn't specify the time zone. The first moment of the calendar day is a different moment in each time zone. Unless you specify a time zone with -setTimeZone: or the string itself carries time zone information, NSDateFormatter assumes that any date strings you ask it to parse are in the current time zone.

So, your dateFromString object represents the first moment of the specified date, 02-06-2012, in your time zone. I expect this is what you wanted. However, you then got confused by the way that NSDate describes itself when logged. As I said, NSDate has to pick some "name" (string representation) for the moment it represents and which name it picks is fairly arbitrary. These days it is picking the name that the moment is known by in UTC. I gather from the log output shown in your question that you are located at UTC+0100. So, the date may look like it's one day earlier but it really is the same moment you specified. In other words, "2012-06-01 23:00:00 +0000" and "2012-06-02 00:00:00 +0100" are two equivalent names for exactly the same moment in time. You just aren't used to seeing the first one and misinterpreted it.

The lesson is that you have to stop relying on NSDate's self-description to be in any particular time zone. Really, you have to not rely on anything about it, since it's not documented. In fact, the docs for -[NSDate description] state, "The representation is not guaranteed to remain constant across different releases of the operating system."

Dhruv's solution seems to help merely because it causes NSDateFormatter and -[NSDate description] to agree on the time zone. But that's unreliable. It wouldn't work on Snow Leopard, for example, because -[NSDate description] used the local time zone instead of UTC in that version of the frameworks.

More importantly, though, it alters the actual moment represented by the NSDate object you get from NSDateFormatter's interpretation of your date string. I suspect you really want that to have a specific meaning – you want the string to be interpreted as being in the local time zone – and his solution thwarts your intent.

tl;dr: you were getting the date you wanted all along; don't rely on -[NSDate description]; don't use Dhruv's solution

dateFromString() returning wrong date swift 3.0

The format of date should be dd/MM/yyyy not dd/mm/yyyy. The mm indicates the minutes and MM indicates the month.

And also add the below line in your code

formatter.timeZone = TimeZone(abbreviation: "GMT+0:00")

This line of code set time zone. If you not, then you get 30/11/2017 in output.

The reason behind this is when string date not contain time then formatter assume that it is midnight and you also not given the timezone so it will take current timezone.

NSDateFormatter dateFromString returning wrong date

Thats the UTC time and it is correct considering the fact that your LocalTime is 1+

var dateString = "17-02-2015"
var dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "dd-MM-yyyy"

var newDate = dateFormatter.dateFromString(dateString)!

println(newDate.descriptionWithLocale(NSLocale.currentLocale())!)

NSDateFormatter return incorrect date from string

The +0000 at the end of the date indicates GMT. All dates are stored relative to GMT; when you convert a date to a string or vice versa using a date formatter, the offset to your time zone is included. You can use NSDateFormatter's -setTimeZone: method to set the time zone used.

In short, you're not doing anything wrong in your code. Use [df stringFromDate:date]; to see that the date is correct. (You can also use NSDate's -descriptionWithCalendarFormat:timeZone:locale:.)

Date-String - String-Date disruption?

You are using capital Y for year instead of y.

Year (in "Week of Year" based calendars). This year designation is used in ISO year-week calendar as defined by ISO 8601, but can be used in non-Gregorian based calendar systems where week date processing is desired. May not always be the same value as calendar year.

Change the format to "EEE, d MMM yyyy HH:mm:ss zzz"

You can read more about ISO week date here: https://en.wikipedia.org/wiki/ISO_week_date

Getting incorrect date format after converting

You have to set Time Zone to UTC (Coordinated Universal Time)

var utcTime = "2020-01-02T00:00:00" //Printing `utcTime` gives "2020-01-02T00:00:00"
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
dateFormatter.locale = Locale(identifier: "en_US")
dateFormatter.timeZone = TimeZone(abbreviation: "UTC")
if let date = dateFormatter.date(from:utcTime) {
  print(date)  //HERE I GET THE DATE AS 2020-01-01 18:30:00 UTC
}

Output :-

Getting wrong date when converting string with timezone

// This lets us parse a date from the server using the RFC3339 format
let rfc3339DateFormatter = DateFormatter()
rfc3339DateFormatter.locale = Locale(identifier: "en_US_POSIX")
rfc3339DateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"
rfc3339DateFormatter.timeZone = TimeZone(secondsFromGMT: 0)

// This string is just a human readable format. 
// The timezone at the end of this string does not mean your date 
// will magically contain this timezone. 
// It just tells the parser what timezone to use to convert this 
// string into a date which is basically just seconds since epoch.
let string = "2019-01-14T00:00:00+08:00"

// At this point the date object has no timezone
let shiftDate = rfc3339DateFormatter.date(from: string)!

// If you want to keep printing in SGT, you have to give the formatter an SGT timezone.
let printFormatter = DateFormatter()
printFormatter.dateStyle = .none
printFormatter.timeStyle = .full
printFormatter.timeZone = TimeZone(abbreviation: "SGT")!
let formattedDate = printFormatter.string(from: shiftDate)

You will notice that it prints 12am. There is nothing wrong with your code. You just misunderstand the Date object. Most people do.

Edit: I used the RFC formatter found in the Apple docs here. The result is the same if you use your formatter. And yes, as rmatty said, there are a few things wrong with your formatter (I stand corrected :))

Convert String to Date Returns nil for afternoon times only

Your date parsing is failing. In your case, its failing because of an invalid hour component in the input string.

Use 24-hour format HH instead of 12-hour format hh.

---

Related Topics