<!--
{
  "availability" : [
    "iOS: 15.0.0 -",
    "iPadOS: 15.0.0 -",
    "macCatalyst: 15.0.0 -",
    "macOS: 12.0.0 -",
    "tvOS: 15.0.0 -",
    "visionOS: 1.0.0 -",
    "watchOS: 8.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "Foundation",
  "identifier" : "/documentation/Foundation/Decimal/FormatStyle/notation(_:)",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Method",
  "symbol" : {
    "kind" : "Instance Method",
    "modules" : [
      "Foundation"
    ],
    "preciseIdentifier" : "s:So9NSDecimala10FoundationE11FormatStyleV8notationyAeC06NumbercD13ConfigurationO8NotationVF"
  },
  "title" : "notation(_:)"
}
-->

# notation(_:)

Modifies the format style to use the specified notation.

```
func notation(_ notation: Decimal.FormatStyle.Configuration.Notation) -> Decimal.FormatStyle
```

## Parameters

`notation`

The notation to apply to the format style.

## Return Value

A decimal format style modified to use the specified notation.

## Discussion

The following example creates a default [`Decimal.FormatStyle`](/documentation/Foundation/Decimal/FormatStyle) for the `en_US` locale, and a second style that uses scientific notation style. It then applies each style to an array of decimal values.

```swift
let defaultStyle = Decimal.FormatStyle(locale: Locale(identifier: "en_US"))
let scientificStyle = defaultStyle.notation(.scientific)
let nums: [Decimal] = [100.1, 1000.2, 10000.3, 100000.4, 1000000.5]
let defaultNums = nums.map { defaultStyle.format($0) } // ["100.1", "1,000.2", "10,000.3", "100,000.4", "1,000,000.5"]
let scientificNums = nums.map { scientificStyle.format($0) } // ["1.001E2", "1.0002E3", "1.00003E4", "1.000004E5", "1E6"]
```

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)