Swift 3: Working with dates

Swift3Dates.swift

//: Playground - noun: a place where people can play
// playing with dates

import Foundation

let date = Date()
let myLocale = Locale(identifier: "en_CA")

//: ### Setting an application-wide `TimeZone`
//: Notice how we use if-let in case the abbreviation is wrong. It will fallback to the default timezone in that case.
if let myTimezone = TimeZone(abbreviation: "PST") {
    print("\(myTimezone.identifier)")
}

//: ### Using a `DateFormatter`
//: You can set a locale and styles to the date formatter. This allows the dates to be formatted in the given language and provides automatic handling of the preferred date formatting in the locale
let formatter = DateFormatter()
formatter.locale = myLocale
formatter.dateStyle = .medium
formatter.timeStyle = .medium

var dateStr = formatter.string(from: date)
print("1. \(dateStr)")

//: Custom date formatter
let dayTimePeriodFormatter = DateFormatter()
dayTimePeriodFormatter.dateFormat = "mm/dd/yyyy"
let dateString = dayTimePeriodFormatter.string(from: Date())
print("1.1. \(dateString)")


var calendar = Calendar(identifier: .gregorian)
calendar.locale = myLocale

//: ### Fetching `DateComponents` off a `Date`
//: Notice how *a locale is needed for the month symbols to be reported correctly*
let dateComponents = calendar.dateComponents([.day, .month, .year], from: date)
let monthName = calendar.monthSymbols[dateComponents.month! - 1]
print ("2. \(dateComponents.day!) \(monthName) \(dateComponents.year!)")


//: #### Constructing a `Date` object from a `DateComponents` object
//: You need a `DateComponents` object and a `Calendar` object instances to do so
if let componentsBasedDate = calendar.date(from: dateComponents) {
    let componentsBasedDateStr = formatter.string(from: componentsBasedDate)
    print("3. \(componentsBasedDateStr)")
}