I have a function where i have to retrieve a date from my own sqlite db of app. I have saved it using the formatter
My work flow
1..Save a date to db on Application did enter background(Saved as String)
2..When application become foreground again i make a date instance at that point of time too. Now i have two date's.
3..Convert both dates to correct format and get the seconds difference.
Convert from date to String-->
let formatter = NSDateFormatter()
formatter.dateFormat = "yyyy-MM-dd HH:mm:ss.Z"
let myString = formatter.stringFromDate(NSDate()) // i get value"2017-05-18 16:49:38.+0530"
But when i reconvert it to NSDate(I Mean when i convert this to string again)-->
let formatter = NSDateFormatter()
formatter.dateFormat = "yyyy-MM-dd HH:mm:ss.Z"
let lastloginDate=formatter.dateFromString(lastLogin) // i get value(Converting back to string \n for checking as the time difference was zero ) 2017-05-18 00:00:00.+0530
I want to compare two dates like a session out service , I do this by getting the calendar components difference of minute. However since its coming like this, the difference his always zero .
let myString1 = formatter.stringFromDate(date1)
let myString2 = formatter.stringFromDate(date2)
print("DATE 1\(myString1) DATE 2 \(myString2)")
let components = calendar.components(flags, fromDate: date2, toDate: date1, options: [])
let diff = components.second
print("Diffrence is \(diff)") // Always zero 😱
Why is this?
Try this one.
let myString1 = formatter.stringFromDate(date1)
let myString2 = formatter.stringFromDate(date2)
print("DATE 1\(myString1) DATE 2 \(myString2)")
let components = NSCalendar.currentCalendar().components([.Month, .Day, .Hour, .Minute, .Second], fromDate: myString1, toDate: myString2, options: [])
let diff = components.second
print("Difference is \(diff)")
Related
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 construct a date from a string. The date is in .islamic calendar. I am using the following code
let StringValue = "1439/01/02"
//constructing the Hijri Date
let HijriFormatter = DateFormatter ()
HijriFormatter.calendar = Calendar(identifier: .islamic)
HijriFormatter.dateFormat="yyyy/MM/dd"
HijriFormatter.timeZone = TimeZone(abbreviation: "GMT+0:00")
let hijriDate = HijriFormatter.date(from: StringValue)
print (hijriDate!)
The output should be similar to the string. However, for some reason I am getting the following output:
2017-09-22 00:00:00 +0000
Any idea of why the code is behaving this way
You can get date components from hijri date using calendar:
let calenadr = Calendar(identifier: .islamicUmmAlQura)
let unitFlags: Set<Calendar.Component> = [.day, .month, .year]
let comps = calenadr.dateComponents(unitFlags, from: hijriDate!)
print(comps.day , comps.month, comps.year)
I have this app written in swift where I get a future date and a future hour (As Unix Timestamp) separately and I want to turned them into one Date() Object so I can converted to Unix Timestamp.
If you now another way to converted directly to Unix Timestamp feel free to post.
This may give you some ideas on how to accomplish what you want:
let calendar = Calendar.current
let currentDate = Date()
// Random future date, 1 month from now
let futureDate = calendar.date(byAdding: .month, value: 1, to: currentDate)!
let futureDateComponents = calendar.dateComponents([.year, .month, .day], from: futureDate)
// Random hour
let futureHour = 2
// Use your future date and your future hour to set the components for the new date to be created
var newDateComponents = calendar.dateComponents([.year, .month, .day, .hour, .minute, .second], from: currentDate)
newDateComponents.year = futureDateComponents.year
newDateComponents.month = futureDateComponents.month
newDateComponents.day = futureDateComponents.day
newDateComponents.hour = futureHour
newDateComponents.minute = 0
newDateComponents.second = 0
// Create a new date from components
let newDate = calendar.date(from: newDateComponents)!
// Convert new date to unix time format
let unixTime = newDate.timeIntervalSince1970
print(newDate) // 2018-03-06 02:00:00 +0000
print(unixTime) // 1520301600.0
Note that in a real project you should avoid force unwrapping (i.e. using '!').
If you have a date string in the form of dd-MM-yyyy, you can convert that to a Date object like so:
let string = "02-06-2018"
let formatter = DateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
formatter.locale = Locale(identifier: "en_US_POSIX") // this is only needed if string is always gregorian but you don't know what locale the device is using
guard let date = formatter.date(from: string) else {
// handle error however you'd like
return
}
Or, if you already have a Date object, then you don't need the above. But regardless, once you have a Date, you can then get a Date by setting the hour, minute, and second as follows:
let hour = 14 // 2pm
guard let result = Calendar.current.date(bySettingHour: hour, minute: 0, second: 0, of: date) else {
// handle error however you'd like
return
}
How would I take a certain amount of days (take away one day) off the current date and print with certain date format to the console.
I'm currently using:
print((Calendar.current as NSCalendar).date(byAdding: .day, value: -1, to: Date(), options: [])!)
Which prints the date and time as:
yyyy-MM-dd HH:MM:SS +0000
But I want it to print like:
dd-MM-yyyy
Is this at all possible?
It's best to break that into a few more easily readable/maintainable lines. First, calculate the date you want, then apply a date formatter.
let yesterday = Calendar.current.date(byAdding: .day, value: -1, to: Date())
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd-MM-yyyy"
print(dateFormatter.stringFromDate(yesterday))
swift 3.0 version
let yesterday = Calendar.current.date(byAdding: .day, value: -1, to: Date())
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd-MM-yyyy"
if let yesterday = yesterday {
print(dateFormatter.string(from: yesterday))
}else{
print("Date incorrectly manipulated")
}
You shouldn't use fixed format for Date format strings. Because you might have users from around the world and they don't see dates in the same way.
Rather you should use template format. You just specify which components you want to show and their order like:
let dateFormatter = DateFormatter()
// dateFormatter.locale = Locale(identifier: "bn-BD") // Enable this line only at the time of your debugging/testing
dateFormatter.dateFormat = DateFormatter.dateFormat(fromTemplate: "ddMMyyyy",
options: 0,
locale: dateFormatter.locale)
let date = Calendar.current.date(byAdding: .day, value: -1, to: Date())
if let date = date {
let dateString = dateFormatter.string(from: date)
print(dateString)
}
You shouldn't set your locale by yourself. It's done by the
framework. You should only set your locale manually only at the time
of testing your app.
In the above example I'm using Locale as "bn-BD" which means Bangla in Bangladesh. You can find your a list of locales here
Using the following overly complex code a date can almost be extracted from a string:
let dateStringArray:[String] = ["29-01-2017 10:41:18:825325012","29-01-2017 10:41:18:894631028"]
let formatString = "dd-MM-yyyy HH:mm:ss:nnnnnnnnn"
let dayRange = formatString.range(of: "dd")
let monthRange = formatString.range(of: "MM")
let yearRange = formatString.range(of: "yyyy")
let hourRange = formatString.range(of: "HH")
let minuteRange = formatString.range(of: "mm")
let secondRange = formatString.range(of: "ss")
let nanoRange = formatString.range(of:"nnnnnnnnn")
let dateString = dateStringArray[0]
let dateComponents = DateComponents( year:Int(dateString.substring(with: yearRange!)),
month:Int(dateString.substring(with: monthRange!)),
day:Int(dateString.substring(with: dayRange!)),
hour:Int(dateString.substring(with: hourRange!)),
minute:Int(dateString.substring(with: minuteRange!)),
second:Int(dateString.substring(with: secondRange!)),
nanosecond:Int(dateString.substring(with: nanoRange!)))
let nano = Int(dateString.substring(with: nanoRange!))
let currentCalendar = Calendar.current
let dateExtracted = currentCalendar.date(from: dateComponents)
print("\(dateExtracted!)")
The output from the final print is: "2017-01-29 10:41:18 +0000\n"
There are issues with this (1) there must be an easier way. (2) & more important, why is the nanosecond component apparently not appearing?
(1) there must be an easier way
Use a date formatter:
let dateString = "29-01-2017 10:41:18:825325012"
let dateFormatter = DateFormatter()
dateFormatter.locale = Locale(identifier: "en_US_POSIX")
dateFormatter.dateFormat = "dd-MM-yyyy HH:mm:ss:SSSSSSSS"
let dateExtracted = dateFormatter.date(from: dateString)!
(2) why is the nanosecond component apparently not appearing?
The description method of Date does not show fractional seconds, but
you can extract it again with
currentCalendar.component(.nanosecond, from: dateExtracted!)
The result may be slightly different from the original nanosecond value
in the string due to rounding errors, because Date stores internally
a floating point number (number of seconds since the reference date
Jan 1, 2001). If you use a date formatter as suggested above then
the resolution is limited to milliseconds (compare NSDateFormatter milliseconds bug).