Swift DateFormatter Cheatsheet, Formulas, And Examples

Manipulating and formatting dates in Swift is a common task. This post presents examples for working with DateFormatter, Date, and other structs that enable parsing, formatting, and extracting components from dates and date strings.

1. Date Formulas Cheatsheet
2. Date Format Cheatsheet
3. Format Date To String Using DateFormatter
   a. timeStyle
   b. dateStyle
   c. locale
   d. calendar
4. Calendar Cheatsheet
5. Convert String To Date
6. Date Components
   a. Create Date From Date Components
   b. Date Components From A Date

Date Formulas Cheatsheet

Date Format Cheatsheet

Format Date To String Using DateFormatter

The dateFormat property on DateFormatter specifies how the DateFormatter instance will parse and format dates. After setting the dateFormat to a format string, call date(from:) with a formatted date string to parse the date string to a Date:

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MM/dd/yyyy"
let date = dateFormatter.date(from: "01/16/2023")
print(date) // Optional(2023-01-16 00:10:00 +0000)

timeStyle

DateFormatter has another interface for specifying the time format of a date, the timeStyle property. The timeStyle property can be set to one of the following values:

let dateFormatter = DateFormatter()
dateFormatter.timeStyle = .medium
let timeString = dateFormatter.string(from: Date())
print(timeString) // "00:10:00 AM"

dateStyle

DateFormatter also has an interface for specifying the date format of a date, the dateStyle property. The dateStyle property can be set to one of the following values:

let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .medium
let dateString = dateFormatter.string(from: Date())
print(dateString) // "Jan 16, 2023"

locale

To control the language and region-specific information in a formatted date, use the locale property on DateFormatter.

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MMMM d, yyyy"
dateFormatter.locale = Locale(identifier: "fr_FR")
let date = dateFormatter.string(from: Date())
print(date) // "janvier 16, 2023"

To set the locale property to the user's device settings, use .autoupdatingCurrent:

dateFormatter.locale = Locale.autoupdatingCurrent

calendar

To control the calendar used to format the Date, use the calendar property on DateFormatter.

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MMMM d, yyyy"
dateFormatter.calendar = Calendar(identifier: .islamic)
let date = dateFormatter.string(from: Date())
print(date) // "Jumada II 22, 1444"

Calendar Cheatsheet

Convert String To Date

In addition to formatting dates and times, use DateFormatter to parse a String into a Date. Just like formatting dates, set dateFormat on the DateFormatter to the format of the date string. Then, call date(from:) passing in a date string to get a parsed Date:

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let dateString = "2023-01-16"
let date = dateFormatter.date(from: dateString)
print(date) // Optional(2023-01-16 00:10:00 +0000)

Date Components

DateComponents is a struct that enables working with specific components of a date, like year, month, or day.

Create Date From Date Components

To create a Date in Swift by specifying each individual date component, use DateComponents:

var components = DateComponents()
components.day = 15
components.month = 1
components.year = 2023
components.hour = 0
components.minute = 10

let date = Calendar.current.date(from: components)

Date Components From A Date

To obtain date components, like the day number, from a Date use DateComponents:

// Use the user's set calendar
let calendar = Calendar.autoupdatingCurrent

// Get the year, month, and day from the date
let components = calendar.dateComponents(
[.year, .month, .day], 
from: Date()
)

// Reference the date components
nowComponents.year
nowComponents.month
nowComponents.day 

Parsing and Formatting Dates In Swift

That's it! By using DateFormatter, Date, Calendar, and DateComponents you can parse, format, and work with date components in Swift.