Subtract 7 days from current date

Question

It seems that I can\'t subtract 7 days from the current date. This is how i am doing it:

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:N         


        

Answer 1

Swift 4.2 - Mutate (Update) Self

Here is another way the original poster can get one week ago if he already has a date variable (updates/mutates itself).

extension Date {
    mutating func changeDays(by days: Int) {
        self = Calendar.current.date(byAdding: .day, value: days, to: self)!
    }
}

Usage

var myDate = Date()       // Jan 08, 2019
myDate.changeDays(by: 7)  // Jan 15, 2019
myDate.changeDays(by: 7)  // Jan 22, 2019
myDate.changeDays(by: -1) // Jan 21, 2019

or

// Iterate through one week
for i in 1...7 {
    myDate.changeDays(by: i)
    // Do something
}