Locale

Locale encapsulates information about linguistic, cultural, and technological conventions and standards. Examples of information encapsulated by a locale include the symbol used for the decimal separator in numbers and the way dates are formatted.

iOS
8.0+
macOS
10.10+
tvOS
9.0+
watchOS
2.0+
struct Locale

Locales are typically used to provide, format, and interpret information about and according to the user’s customs and preferences. They are frequently used in conjunction with formatters. Although you can use many locales, you usually use the one associated with the current user.