I am using Swift 3, and i would like to print the every day between two dates.
For example:
08-10-2017 -> Start Date
08-15-2017 -> End Date
Should print:
08-10-2017
08-11-2017
08-12-2017
08-13-2017
08-14-2017
08-15-2017
I want to get ranges in two specific date, can someone help me out please. I tried to put these two dates to for loop but no chance.
You need to create a calendar based dates, and start increasing start date until you reach end date. Here is a code snippet, how to do it:
func showRange(between startDate: Date, and endDate: Date) {
// Make sure startDate is smaller, than endDate
guard startDate < endDate else { return }
// Get the current calendar, i think in your case it should some fscalendar instance
let calendar = Calendar.current
// Calculate the endDate for your current calendar
let calendarEndDate = calendar.startOfDay(for: endDate)
// Lets create a variable, what we can increase day by day
var currentDate = calendar.startOfDay(for: startDate)
// Run a loop until we reach the end date
while(currentDate <= calendarEndDate) {
// Print the current date
print(currentDate)
// Add one day at the time
currentDate = Calendar.current.date(byAdding: .day, value: 1, to: currentDate)!
}
}
Usage:
let today = Date()
let tenDaysLater = Calendar.current.date(byAdding: .day, value: 10, to: today)!
showRange(between: today, and: tenDaysLater)
Related
I am having a small issue with getting the total days in a month using Swift.
I have extended the Date class and created this function:
func daysInMonth() -> Int {
print(self.day) ##30
print(self.month) ##12
print(self) ## 2021-11-30 23:46:29 +0000
print(Calendar.current.range(of: .day, in: .month, for: self)?.count) ##31
return Calendar.current.range(of: .day, in: .month, for: self)?.count ?? 0
}
I have set the Date&Time to the 30th of November, at 11:45 PM in the settings of my Mac, in Preferences.
I called the above function at 11:46 PM and obtained the above results (inline, next to the print statements).
The date output is correct as well as the day. The month output is wrong and the result is 31 days in the month of November.
If I run this exact same code before 10:00 PM, I get the right result which is 30 days.
Does anyone know why this is happening?
Thank you,
Paprika
It's a GMT offset issue combined with the current day in a month.
When you create a date without set a day, it will be set to the first day of the month.
So, if your timezone offset is for example -4 means your are 4 hours behind the GMT 0 and by default the timezone defined at Calendar.current is equal the system timezone. So what it means? Means you'll obtain the previous month if you test it in a boundary of 23 + (-4) or the next month if your offset is positive.
You can test this behaviour copying'n paste the following code in the Playground.
func getDaysInMonth(month: Int, year: Int, offset: Int = 0) -> Int? {
let someDate = DateComponents(year: year, month: month, hour: 3)
var current = Calendar.current
let timezone = TimeZone(secondsFromGMT: 60 * 60 * offset)!
current.timeZone = timezone
guard let someDay = current.date(from: someDate) else { return nil }
print("date: \(someDay)") // this will always
return someDay.daysInCurrentMonth
}
for hour in -12...12 {
print("hour: \(hour)\ndays: \(getDaysInMonth(month: 10, year: 2021, offset: hour) ?? -1)")
print("---\n")
}
extension Date {
var daysInCurrentMonth: Int? {
Calendar.current.range(of: .day, in: .month, for: self)?.count
}
}
Notice the days will change starting by your current system time zone (notice only the month will change).
How to fix this?
In your case, I guess you just want to show how many days a month have, so you can just set the to zero like this:
TimeZone(secondsFromGMT: 0)
Do this change at a instance of Calendar.current and check if it works for you.
It appears there something wrong with your Date extension methods for .day and .month.
Without seeing code it's hard to determine what the problem is though. Below is some code for returning the current month (Int) and current numbered day of month (Int)
extension Date
{
var month: Int
{
let date = Date()
let calendar = Calendar.current
let components = calendar.dateComponents([.month], from: date)
return components.month
}
var day: Int
{
let date = Date()
let calendar = Calendar.current
let components = calendar.dateComponents([.day], from: self)
return components.day
}
}
Please also ensure your time/date settings are correct on your mac/simulator/device. If these are wrong - it could have been jumping to a different month if you were in a timezone that was ahead a few hours.
I have an app that uses Core Data. I have a function
func showHistory(for days:Int)->Int {
var historyForXDaysInt = Int()
var calendar = Calendar.current
calendar.locale = .current
calendar.timeZone = .current
var startDate:Date?
var endDate = Date()
switch days{
case 1:
startDate = Date()
startDate = calendar.startOfDay(for: startDate!)
default:
startDate = calendar.date(byAdding: .day, value: -days+1, to: Date())
startDate = calendar.startOfDay(for: startDate!)
}
//There is more to this function, where I make the request but I just included the relevant part for my question
}
My question: I am trying to get relevant data from Core Data between two dates via the predicate let predicate = NSPredicate(format: "(completedDate >= %#) AND (completedDate <= %#)", startDate! as NSDate, endDate as NSDate).There is a completedDate property in my core data model. When I make the request I get data for 1 more day than I asked for. I tried solving it with adding 1 to the days variable. For example, if I am asking for 2 days of data (meaning days = 2) I get data for 3 days. What might be the cause? Why does it not work as intended without the +1 ?
I'm grabbing data from an api, and one of the values I'm getting is for day of the week, the data returned from api looks like this:
"time": 1550376000
I created this function to get the date:
func getDate(value: Int) -> String {
let date = Calendar.current.date(byAdding: .day, value: value, to: Date())
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "E"
return dateFormatter.string(from: date!)
}
but was told there is a much safer way to get it instead of assuming we get consecutive days starting with today. Does anyone know how to build a date out of the time field (it is seconds since midnight 1970) and then use Calendar and DateComponent to figure out the day?
Looks like you are receiving json data so you should structure your data and conform to Decodable protocol to convert your data to an object properly structured.
struct Object: Decodable {
let time: Date
}
Don't forget to set the decoder dateDecodingStrategy property to secondsSince1970
do {
let obj = try decoder.decode(Object.self, from: Data(json.utf8))
let date = obj.time // "Feb 17, 2019 at 1:00 AM"
print(date.description(with: .current))// "Sunday, February 17, 2019 at 1:00:00 AM Brasilia Standard Time\n"
} catch {
print(error)
}
Then you just need to get the weekday component (1...7 = Sun...Sat) and get the calendar shortWeekdaySymbols (localised), subtract 1 from the component value and use it as index to get correspondent symbol. Same approach I used in this post How to print name of the day of the week? to get the full week day name:
extension Date {
var weekDay: Int {
return Calendar.current.component(.weekday, from: self)
}
var weekdaySymbolShort: String {
return Calendar.current.shortWeekdaySymbols[weekDay-1]
}
}
print(date.weekdaySymbolShort) // "Sun\n"
You can use Calendar to get date component from the Date:
let date = Date(timeIntervalSince1970: time)// time is your value 1550376000
let timeComponents = Calendar.current.dateComponents([.weekday, .day, .month, .year], from: date)
print("\(timeComponents.weekday) \(timeComponents.day!) \(timeComponents.month!) \(timeComponents.year!)") // print "7 16 2 2019"
print("\(\(Calendar.current.shortWeekdaySymbols[timeComponents.weekday!-1]))") // print "Sat"
Hope this helps.
How to get the current date in unix-epoch?
timeIntervalSince1970 prints the current time. Is there any way to get today's time at 12 AM?
For example, The current time is : Jan 7, 2018 5:30 PM. timeIntervalSince1970 will print the current time i.e. 1546903800000.
Current date in epoch system will be Jan 7, 2018 00:00 AM. i.e 1546848000000
This can be done very simply using the following code. No need for date components or other complications.
var calendar = Calendar.current
// Use the following line if you want midnight UTC instead of local time
//calendar.timeZone = TimeZone(secondsFromGMT: 0)
let today = Date()
let midnight = calendar.startOfDay(for: today)
let tomorrow = calendar.date(byAdding: .day, value: 1, to: midnight)!
let midnightEpoch = midnight.timeIntervalSince1970
let tomorrowEpoch = tomorrow.timeIntervalSince1970
I would do this with components.
Assuming you need time in seconds as defined by time(2). If you need in milliseconds as defined by time(3), then you can multiply it out by 1000.
// Get right now as it's `DateComponents`.
let now = Calendar.current.dateComponents(in: .current, from: Date())
// Create the start of the day in `DateComponents` by leaving off the time.
let today = DateComponents(year: now.year, month: now.month, day: now.day)
let dateToday = Calendar.current.date(from: today)!
print(dateToday.timeIntervalSince1970)
// Add 1 to the day to get tomorrow.
// Don't worry about month and year wraps, the API handles that.
let tomorrow = DateComponents(year: now.year, month: now.month, day: now.day! + 1)
let dateTomorrow = Calendar.current.date(from: tomorrow)!
print(dateTomorrow.timeIntervalSince1970)
You can get yesterday by subtracting 1.
If you need this in the universal time (UTC, GMT, Z… whatever name you give universal time), then use the following.
let utc = TimeZone(abbreviation: "UTC")!
let now = Calendar.current.dateComponents(in: utc, from: Date())
Use this extension to get today's and tomorrow's date
extension Date {
static var tomorrow: Date { return Date().dayAfter }
static var today: Date {return Date()}
var dayAfter: Date {
return Calendar.current.date(byAdding: .day, value: 1, to: Date())!
}
}
Also try adding following code in date extension:
extension Date
{
var startOfDay: Date
{
return Calendar.current.startOfDay(for: self)
}
func getDate(dayDifference: Int) -> Date {
var components = DateComponents()
components.day = dayDifference
return Calendar.current.date(byAdding: components, to:startOfDay)!
}
}
You can use the following method to get any date by adding days or months or years
by specifying the Calendar Component and the increment value of this component:
func getSpecificDate(byAdding component: Calendar.Component, value: Int) -> Date {
let noon = Calendar.current.date(bySettingHour: 12, minute: 0, second: 0, of: self)!
return Calendar.current.date(byAdding: component, value: value, to: noon)!
}
Where the component wil be one from the following option :
( .day , .month , .year ) and the value will be the amount you want to add for this component
for example to get the next year date you can use the following code:
var nextYear = getSpecificDate(byAdding: .year, value: 1).timeIntervalSince1970
I have a dictionary like this:
var dic = [NSDate: Int]()
it is used in my iOS to-do app to get the number of finished tasks of a particular date. I only care about the year, month and day sections in NSDate and also want to be able to get the number of tasks in a particular date using this dictionary, how can I do that? thanks.
Instead of storing your date as NSDate in your dictionary you can save it as String so that comparison will be easier. Use following code to store it as a string
func dateFromString(date : NSDate) -> String {
var dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
return dateFormatter.stringFromDate(date)
}
You can pass NSDate() to above function and it will give you string containing only year, month and date. For retrieving your data from dictionary use following.
func dateFrom(year:Int, month:Int, day:Int) -> String {
let components = NSDateComponents()
components.year = year
components.month = month
components.day = day
let gregorian = NSCalendar(identifier:NSCalendarIdentifierGregorian)
let date = gregorian!.dateFromComponents(components)
return dateFromString(date!)
}
You can pass year, month and date to above function and it will return corresponding date in string format. So your dictionary operations will look like
dict[dateFromString(NSDate())] = 1 //for insertion or updation
let numOfTasks = dict[dateFrom(2016, month: 1, day: 15)] //to get task for any particular day
EDIT
If you want to proceed with NSDate as key for your dictionary then you'll have to modify above code as follows. dateFrom will return date with year,month and date of your choice, and time will be some constant value. Time will be set to midnight in your current time zone if you don't set it.
func dateFrom(year:Int, month:Int, day:Int) -> NSDate {
let components = NSDateComponents()
components.year = year
components.month = month
components.day = day
let gregorian = NSCalendar(identifier:NSCalendarIdentifierGregorian)
let date = gregorian!.dateFromComponents(components)
return date!
}
And for getting current date use following so that you store date object with current year, date, month and time to some constant value.
func getCurrentDate()->NSDate {
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
let components = calendar.components([.Day , .Month , .Year], fromDate: date)
return dateFrom(components.year, month: components.month, day: components.day)
}
Usage will be as follows
dict[getCurrentDate()] = i //for insertion or updation
let numOfTasks = dict[dateFrom(2016, month: 1, day: 15)] //to get task for any particular day