---
title: "format(_:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/decimal/formatstyle/format(_:)"
---

# format(_:)

Formats a decimal value using this style.

## Declaration

```swift
func format(_ value: Decimal) -> String
```

## Parameters

- `value`: The decimal value to format.

## Return Value

Return Value A string representation of value formatted according to the style’s configuration.

## Discussion

Discussion Use this method when you want to create a single style instance and then use it to format multiple decimal values. The following example creates a style that uses the en_US locale and then adds the scientific modifier. It then applies this style to all of the decimal values in an array. let scientificStyle = Decimal.FormatStyle(     locale: Locale(identifier: "en_US"))     .notation(.scientific) let nums: [Decimal] = [100.1, 1000.2, 10000.3, 100000.4, 1000000.5] let formattedNums = nums.map { scientificStyle.format($0) } // ["1.001E2", "1.0002E3", "1.00003E4", "1.000004E5", "1E6"] To format a single floating-point value, use the Decimal instance method formatted(_:), passing in an instance of Decimal.FormatStyle, or formatted() to use a default style.