How to convert dates and times to a string using DateFormatter

Swift version: 5.10

Paul Hudson @twostraws May 23rd 2022

If you want to get a string from a Date, Apple’s DateFormatter class has everything you need: you can get short dates, long dates, dates with times, and can even go the opposite way to give you a Date from a string.

There are four primary ways you’re going to use it:

Converting a Date instance to a string using one of the built-in date formats.
Converting a Date instance to a string using one of the built-in time formats.
Converting a Date instance to a string using a completely custom format.
Converting a string instance to a Date.

Below are examples of each to get you started.

First, this converts a Date to a short date string using dateStyle:

let today = Date.now
let formatter1 = DateFormatter()
formatter1.dateStyle = .short
print(formatter1.string(from: today))

That will print something like “12/31/2019” depending on the user’s locale.

Second, this converts the same date to a medium time string using timeStyle:

let formatter2 = DateFormatter()
formatter2.timeStyle = .medium
print(formatter2.string(from: today))

That will print something like “20:27:32” or “8:27:32pm” depending on the user’s locale.

Third, this converts the same date to a date and time string using a custom date format:

let formatter3 = DateFormatter()
formatter3.dateFormat = "HH:mm E, d MMM y"
print(formatter3.string(from: today))

That will print something like “20:32 Wed, 30 Oct 2019”.

Finally, this attempts to convert a string to a date

let string = "20:32 Wed, 30 Oct 2019"
let formatter4 = DateFormatter()
formatter4.dateFormat = "HH:mm E, d MMM y"
print(formatter4.date(from: string) ?? "Unknown date")

date(from:) returns an optional Date because it might be given a string containing an invalid value, so that code uses nil coalescing to make sure there’s a default value printed.