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# ISO8601DateFormatter

A formatter that converts between dates and their ISO 8601 string representations.

```
class ISO8601DateFormatter
```

## Overview

The [`ISO8601DateFormatter`](/documentation/Foundation/ISO8601DateFormatter) class generates and parses string representations of dates following the [ISO 8601](http://www.iso.org/iso/home/standards/iso8601) standard. Use this class to create ISO 8601 representations of dates and create dates from text strings in ISO 8601 format.

> Tip:
> In Swift, you can use ``doc://com.apple.foundation/documentation/Foundation/Date/ISO8601FormatStyle`` rather than ``doc://com.apple.foundation/documentation/Foundation/ISO8601DateFormatter``. The ``doc://com.apple.foundation/documentation/Foundation/FormatStyle`` API offers a declarative idiom for customizing the formatting of various types. Also, Foundation caches identical ``doc://com.apple.foundation/documentation/Foundation/FormatStyle`` instances, so you don’t need to pass them around your app, or risk wasting memory with duplicate formatters.

## Topics

### Configuring the Formatter

[`formatOptions`](/documentation/Foundation/ISO8601DateFormatter/formatOptions)

Options for generating and parsing ISO 8601 date representations. See [`ISO8601DateFormatter.Options`](/documentation/Foundation/ISO8601DateFormatter/Options) for possible values.

[`timeZone`](/documentation/Foundation/ISO8601DateFormatter/timeZone)

The time zone used to create and parse date representations. When unspecified, GMT is used.

### Creating ISO 8601 Date Formatters

[`init()`](/documentation/Foundation/ISO8601DateFormatter/init())

Initializes an ISO 8601 date formatter with default format, time zone, and options.

### Converting ISO 8601 Dates

[`string(from:)`](/documentation/Foundation/ISO8601DateFormatter/string(from:))

Creates and returns an ISO 8601 formatted string representation of the specified date.

[`date(from:)`](/documentation/Foundation/ISO8601DateFormatter/date(from:))

Creates and returns a date object from the specified ISO 8601 formatted string representation.

[`string(from:timeZone:formatOptions:)`](/documentation/Foundation/ISO8601DateFormatter/string(from:timeZone:formatOptions:))

Creates a representation of the specified date with a given time zone and format options.

### Constants

[`ISO8601DateFormatter.Options`](/documentation/Foundation/ISO8601DateFormatter/Options)

Options used to generate and parse ISO 8601 date representations.


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