swift 4 current year, month, day

to get current date in the format "yyyy-MM-dd HH:mm:ss"

let date = Date()
let format = DateFormatter()
format.dateFormat = "yyyy-MM-dd HH:mm:ss"
let formattedDate = format.string(from: date)
print(formattedDate)

if you need current day, month, year.
use Calendar class

let calendar = Calendar.current
calendar.component(.year, from: date)
calendar.component(.month, from: date)
calendar.component(.day, from: date) 

all returns int. if the moth is September .month would return 9.
day of week.

calendar.component(.weekday, from: date)

It will return 1 when it is in Sunday as in Gregorian Calendar.

add month

var lastMonthDate = Calendar.current.date(byAdding: .month, value: -1, to: date)
calendar.component(.month, from:lastMonthDate!)

it gives you the number of last month.

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