Swift Date formatting and String to Date Conversion

The DateFormatter class is a subclass of the Formatter abstract class that can be used to convert a Date object into a human-readable string. It can also be used to convert a String representation of a date into a Date object. The DateFormatter type has five predefined styles that we can use.

• Style = .none 
• No format 
• Style = .short 
• 3/24/19, 11:01 PM
• Style = .medium 
• Mar 24, 2019 at 11:01:48 PM
• Style = .long 
• March 24, 2019 at 11:01:48 PM EDT
• Style = .full 
• Sunday, March 24, 2019 at 11:01:48 PM Eastern Daylight Time

import UIKit

let currentDate = Date()
var myFormat = DateFormatter()

//Just Date = 3/24/19
myFormat.dateStyle = .short
myFormat.timeStyle = .none
print(myFormat.string(from: currentDate))

//Just Time = 10:46 PM
myFormat.dateStyle = .none
myFormat.timeStyle = .short
print(myFormat.string(from: currentDate))
//Result = 3/24/19

//Short Date and Time = 10:46 PM
myFormat.dateStyle = .short
myFormat.timeStyle = .short
print(myFormat.string(from: currentDate))

//Medium Date and Time = Mar 24, 2019 at 10:49:04 PM
myFormat.dateStyle = .medium
myFormat.timeStyle = .medium
print(myFormat.string(from: currentDate))

//Long Date and Time = March 24, 2019 at 10:49:04 PM EDT
myFormat.dateStyle = .long
myFormat.timeStyle = .long
print(myFormat.string(from: currentDate))


//Full Date and Time = Sunday, March 24, 2019 at 10:49:04 PM Eastern Daylight Time
myFormat.dateStyle = .full
myFormat.timeStyle = .full
print(myFormat.string(from: currentDate))

Convert Date using a Custom String Format

For custom formatting we have to use standard characters based on how we want the date to display. The DateFormatter instance will replace these characters with the appropriate values. The following table shows some of the formatting values that we can use...

Standard String	Description	Output
yy	Two-digit year	19, 20, 02
yyyy	Four-digit year	2019, 2020, 2002
MM	Two-digit month	04, 05, 06
MMM	Three-letter month	Apr, May, Jun
MMMM	Full month name	April, May, June
dd	Two-digit day	10, 11, 20
EEE	Three-letter day	Mon, Sat, Sun
EEEE	Full day	Monday, Saturday, Sunday
a	Period of day	AM, PM
hh	Two-digit hour	03, 04, 06
HH	24-hour clock	11, 14, 17
mm	Two-digit minute	22, 35, 45
ss	Two-digit seconds	22, 35, 45

//Custom Date and Time formatting = 2019-03-24 22:52:05
myFormat.dateFormat = "YYYY-MM-dd HH:mm:ss"
print(myFormat.string(from: currentDate))

//Get Date object from String Value
let dateString = "2019-03-24 13:12:01"
myFormat.dateFormat = "YYYY-MM-dd HH:mm:ss"
myFormat.timeZone = TimeZone.current
let newDate = myFormat.date(from: dateString)
print(newDate as Any)