Create string array of dates from Dates range - ios

Question

I have Date() properties. startingAt and endingAt. And an array of Date(), which are alreadyRegistred. I have to create an array of strings with dates between startingAt and endingAt. StartingAt and endingAt are included and the last requirement is to exclude alreadyRegistred dates.
Do you have some elegant idea, how to do it? Thanks for help!
Edit: Maximum number of dates in final array will be about 7 days.

Answer 1

Dont forget that a Date is basically just a timestamp, and that you can have access to the addingTimeInterval(_:) method.
Knowing that, is very easy to do some calculation between two dates.
I do not have the whole knowledge about your required business logic, but here is a naive implementation that generates Dates between two dates. I'm sure you can run it in a playground and explore a little bit.
import UIKit
func intervalDates(from startingDate:Date, to endDate:Date, with interval:TimeInterval) -> [Date] {
guard interval > 0 else { return [] }
var dates:[Date] = []
var currentDate = startingDate
while currentDate <= endDate {
currentDate = currentDate.addingTimeInterval(interval)
dates.append(currentDate)
}
return dates
}
let startingDate = Date() // now
let endDate = Date(timeIntervalSinceNow: 3600 * 24 * 7) // one week from now
let intervalBetweenDates:TimeInterval = 3600 * 3// three hours
let dates:[Date] = intervalDates(from: startingDate, to: endDate, with: intervalBetweenDates)
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .long
dateFormatter.timeStyle = .long
let dateStrings = dates.map{dateFormatter.string(from: $0)}
print("NOW : \(startingDate)")
for (index, string) in dateStrings.enumerated() {
print("\(index) : \(string)")
}
print("END DATE : \(endDate)")

Answer 2

Try this and see:
// Start & End date string
let startingAt = "01/01/2018"
let endingAt = "08/03/2018"
// Sample date formatter
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd/MM/yyyy"
// start and end date object from string dates
var startDate = dateFormatter.date(from: startingAt) ?? Date()
let endDate = dateFormatter.date(from: endingAt) ?? Date()
// String date array, to be excluded
let alreadyRegistred = ["01/01/2018", "15/01/2018", "10/02/2018", "20/02/2018", "05/03/2018"]
// Actual operational logic
var dateRange: [String] = []
while startDate <= endDate {
let stringDate = dateFormatter.string(from: startDate)
startDate = Calendar.current.date(byAdding: .day, value: 1, to: startDate) ?? Date()
if (alreadyRegistred.contains(stringDate)) {
continue
} else {
dateRange.append(stringDate)
}
}
print("Resulting Array - \(dateRange)")
Here is result:
Resulting Array - ["02/01/2018", "03/01/2018", "04/01/2018", "05/01/2018", "06/01/2018", "07/01/2018", "08/01/2018", "09/01/2018", "10/01/2018", "11/01/2018", "12/01/2018", "13/01/2018", "14/01/2018", "16/01/2018", "17/01/2018", "18/01/2018", "19/01/2018", "20/01/2018", "21/01/2018", "22/01/2018", "23/01/2018", "24/01/2018", "25/01/2018", "26/01/2018", "27/01/2018", "28/01/2018", "29/01/2018", "30/01/2018", "31/01/2018", "01/02/2018", "02/02/2018", "03/02/2018", "04/02/2018", "05/02/2018", "06/02/2018", "07/02/2018", "08/02/2018", "09/02/2018", "11/02/2018", "12/02/2018", "13/02/2018", "14/02/2018", "15/02/2018", "16/02/2018", "17/02/2018", "18/02/2018", "19/02/2018", "21/02/2018", "22/02/2018", "23/02/2018", "24/02/2018", "25/02/2018", "26/02/2018", "27/02/2018", "28/02/2018", "01/03/2018", "02/03/2018", "03/03/2018", "04/03/2018", "06/03/2018", "07/03/2018", "08/03/2018"]

Answer 3

let startDate = Date()
let endDate = Date().addingTimeInterval(24*60*60*10) // i did this to get the end date for now
var stringdateArray = [String]()
if let days = getNumberofDays(date1: startDate, date2: endDate) {
for i in 0...days-1 {
let date = startDate.addingTimeInterval(Double(i)*24*3600)
let stringDate = getStringDate(fromDate: date, havingFormat: "yyyy-MM-dd")
if !(alreadyRegisteredArray.contains(stringDate)) { // checking if already registered
stringdateArray.append(stringDate)
}
}
}
and our helper method
let dateFormatter = DateFormatter()
func getStringDate(fromDate: Date,havingFormat: String) -> String {
dateFormatter.dateFormat = havingFormat
dateFormatter.amSymbol = "AM"
dateFormatter.pmSymbol = "PM"
let date = dateFormatter.string(from: fromDate)
return date
}
func getNumberofDays(date1: Date, date2: Date) -> Int? {
let calendar = NSCalendar.current
let date1 = calendar.startOfDay(for: date1)
let date2 = calendar.startOfDay(for: date2)
let components = calendar.dateComponents([.day], from: date1, to: date2)
return components.day
}