[ACCEPTED]-How does one subtract hours from an NSDate?-nsdate
NSDate *newDate = [theDate dateByAddingTimeInterval:-3600*4];
NSDate *newDate = [[[NSDate alloc] initWithTimeInterval:-3600*4
sinceDate:theDate]] autorelease];
0
NSCalendar is the general API for changing 3 dates based on human time units. For this, you 2 can use NSCalendar's -dateByAddingComponents:toDate:options: with a negative number 1 of hours.
In Swift 4 :
var baseDate = ... // something
let dateMinus4Hours = Calendar.current.date(byAdding: .hour, value: -4, to: baseDate)
don't go with 24*3600 and stuff, that's 1 asking for trouble.
Since iOS 8 there is the more convenient 1 dateByAddingUnit:
Swift 2.x
//subtract 3 hours
let calendar = NSCalendar.autoupdatingCurrentCalendar()
newDate = calendar.dateByAddingUnit(.Hour, value: -3, toDate: originalDate, options: [])
//in Swift 3
//subtract 3 hours
let calendar = NSCalendar.autoupdatingCurrent
newDate = calendar.date(byAdding:.hour, value: -3, to: originalDate)
0
Here a function which might be useful as 4 it returns the date -4 h considering that 3 this may also change the date and the month 2 and eventually the year. the .searchBackward 1 option is the important part :)
public static func correctSecondComponent(date: Date, calendar: Calendar = Calendar(identifier: Calendar.Identifier.gregorian))->Date {
let hour = calendar.component(.hour, from: date)
let e = (calendar as NSCalendar).date(byAdding: NSCalendar.Unit.hour, value: -4, to: date, options:.searchBackwards)!
return e
}
dateFromString function returns NSDate, not 2 NSString. you should change,
NSDate * theDate 1 = [dateFormatter dateFromString:datetemp];
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