How does one subtract hours from an NSDate?

Question

I would like to subtract 4 hours from a date. I read the date string into an NSDate object use the following code:

NSDateFormatter * dateFormatter = [[[NSDat         


        

Answer 1

Here a function which might be useful as it returns the date -4 h considering that this may also change the date and the month and eventually the year. the .searchBackward 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
}