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

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 asking for trouble.