# FloatingPointFormatStyle A structure that converts between floating-point values and their textual representations. ``` struct FloatingPointFormatStyle where Value : BinaryFloatingPoint ``` ## Overview Instances of [`FloatingPointFormatStyle`](/documentation/Foundation/FloatingPointFormatStyle) create localized, human-readable text from numbers and parse string representations of numbers into instances of types. All of the Swift standard library’s floating-point types, such as , , and , conform to , and therefore work with this format style. [`FloatingPointFormatStyle`](/documentation/Foundation/FloatingPointFormatStyle) includes two nested types, [`FloatingPointFormatStyle.Percent`](/documentation/Foundation/FloatingPointFormatStyle/Percent) and [`FloatingPointFormatStyle.Currency`](/documentation/Foundation/FloatingPointFormatStyle/Currency), for working with percentages and currencies, respectively. Each format style includes a configuration that determines how it represents numeric values, for things like grouping, displaying signs, and variant presentations like scientific notation. [`FloatingPointFormatStyle`](/documentation/Foundation/FloatingPointFormatStyle) and [`FloatingPointFormatStyle.Percent`](/documentation/Foundation/FloatingPointFormatStyle/Percent) include a [`NumberFormatStyleConfiguration`](/documentation/Foundation/NumberFormatStyleConfiguration), and [`FloatingPointFormatStyle.Currency`](/documentation/Foundation/FloatingPointFormatStyle/Currency) includes a [`CurrencyFormatStyleConfiguration`](/documentation/Foundation/CurrencyFormatStyleConfiguration). You can customize numeric formatting for a style by adjusting its backing configuration. The system automatically caches unique configurations of a format style to enhance performance. > Note: > Foundation provides another format style type, ``doc://com.apple.foundation/documentation/Foundation/IntegerFormatStyle``, for working with numbers that conform to . For Foundation’s ``doc://com.apple.foundation/documentation/Foundation/Decimal`` type, use ``doc://com.apple.foundation/documentation/Foundation/Decimal/FormatStyle``. ### Formatting floating-point values Use the method to create a string representation of a floating-point value using the default [`FloatingPointFormatStyle`](/documentation/Foundation/FloatingPointFormatStyle) configuration. ```swift let formattedDefault = 12345.67.formatted() // formattedDefault is "12,345.67" in the en_US locale. // Other locales may use different separator and grouping behavior. ``` You can specify a format style by providing an argument to the method. The following example shows the number `0.1` represented in each of the available styles, in the `en_US` locale: ```swift let number = 0.1 let formattedNumber = number.formatted(.number) // formattedNumber is "0.1". let formattedPercent = number.formatted(.percent) // formattedPercent is "10%". let formattedCurrency = number.formatted(.currency(code: "USD")) // formattedCurrency is "$0.10". ``` Each style provides methods for updating its numeric configuration, including the number of significant digits, grouping length, and more. You can specify a numeric configuration by calling as many of these methods as you need in any order you choose. The following example shows the same number with default and custom configurations: ```swift let exampleNumber = 123456.78 let defaultFormatting = exampleNumber.formatted(.number) // defaultFormatting is "123 456,78" for the "fr_FR" locale. // defaultFormatting is "123,456.78" for the "en_US" locale. let customFormatting = exampleNumber.formatted( .number .grouping(.never) .sign(strategy: .always())) // customFormatting is "+123456.78" ``` ### Creating a floating-point format style instance The previous examples use static factory methods like [`number`](/documentation/Foundation/FormatStyle/number-8c8rj) to create format styles within the call to the method. You can also create a [`FloatingPointFormatStyle`](/documentation/Foundation/FloatingPointFormatStyle) instance and use it to repeatedly format different values, with the [`format(_:)`](/documentation/Foundation/FloatingPointFormatStyle/format(_:)) method: ```swift let percentFormatStyle = FloatingPointFormatStyle.Percent() percentFormatStyle.format(0.5) // "50%" percentFormatStyle.format(0.855) // "85.5%" percentFormatStyle.format(1.0) // "100%" ``` ### Parsing floating-point values You can use [`FloatingPointFormatStyle`](/documentation/Foundation/FloatingPointFormatStyle) to parse strings into floating-point values. You can define the format style within the type’s initializer or pass in a format style created outside the function, as shown here: ```swift let price = try? Double("$3,500.63", format: .currency(code: "USD")) // 3500.63 let priceFormatStyle = FloatingPointFormatStyle.Currency(code: "USD") let salePrice = try? Double("$731.67", format: priceFormatStyle) // 731.67 ``` ### Matching regular expressions Along with parsing numeric values in strings, you can use theSwift regular expression domain-specific language to match and capture numeric substrings. The following example defines a percentage format style to match a percentage value using `en_US` numeric conventions. The rest of the regular expression ignores any characters prior to a `": "` sequence that precedes the percentage substring. ```swift import RegexBuilder let source = "Percentage complete: 55.1%" let matcher = Regex { OneOrMore(.any) ": " Capture { One(.localizedDoublePercentage(locale: Locale(identifier: "en_US"))) } } let match = source.firstMatch(of: matcher) let localizedPercentage = match?.1 print("\(localizedPercentage!)") // 0.551 ``` ## Topics ### Creating a floating-point format style [`init(locale:)`](/documentation/Foundation/FloatingPointFormatStyle/init(locale:)) Creates a floating-point format style that uses the given locale. ### Formatting floating-point values [`format(_:)`](/documentation/Foundation/FloatingPointFormatStyle/format(_:)) Formats a floating-point value, using this style. ### Customizing style behavior [`decimalSeparator(strategy:)`](/documentation/Foundation/FloatingPointFormatStyle/decimalSeparator(strategy:)) Modifies the format style to use the specified decimal separator display strategy. [`grouping(_:)`](/documentation/Foundation/FloatingPointFormatStyle/grouping(_:)) Modifies the format style to use the specified grouping. [`locale(_:)`](/documentation/Foundation/FloatingPointFormatStyle/locale(_:)) Modifies the format style to use the specified locale. [`notation(_:)`](/documentation/Foundation/FloatingPointFormatStyle/notation(_:)) Modifies the format style to use the specified notation. [`precision(_:)`](/documentation/Foundation/FloatingPointFormatStyle/precision(_:)) Modifies the format style to use the specified precision. [`rounded(rule:increment:)`](/documentation/Foundation/FloatingPointFormatStyle/rounded(rule:increment:)) Modifies the format style to use the specified rounding rule and increment. [`scale(_:)`](/documentation/Foundation/FloatingPointFormatStyle/scale(_:)) Modifies the format style to use the specified scale. [`sign(strategy:)`](/documentation/Foundation/FloatingPointFormatStyle/sign(strategy:)) Modifies the format style to use the specified sign display strategy for displaying or omitting sign symbols. [`Configuration`](/documentation/Foundation/FloatingPointFormatStyle/Configuration) The type the format style uses for configuration settings. [`NumberFormatStyleConfiguration`](/documentation/Foundation/NumberFormatStyleConfiguration) Configuration settings for formatting numbers of different types. ### Accessing style locale [`locale`](/documentation/Foundation/FloatingPointFormatStyle/locale) The locale of the format style. ### Applying currency styles [`Currency`](/documentation/Foundation/FloatingPointFormatStyle/Currency) A format style that converts between floating-point currency values and their textual representations. ### Applying measurement styles [`FormatStyle`](/documentation/Foundation/Measurement/FormatStyle) A type that provides localized representations of measurements. ### Applying list styles [`ListFormatStyle`](/documentation/Foundation/ListFormatStyle) A type that formats lists of items with a separator and conjunction appropriate for a given locale. ### Creating attributed strings [`attributed`](/documentation/Foundation/FloatingPointFormatStyle/attributed-swift.property) An attributed format style based on the floating-point format style. [`Attributed`](/documentation/Foundation/FloatingPointFormatStyle/Attributed-swift.struct) A format style that converts integers into attributed strings. ### Parsing floating-point numbers [`parseStrategy`](/documentation/Foundation/FloatingPointFormatStyle/parseStrategy) The parse strategy that this format style uses. [`FloatingPointParseStrategy`](/documentation/Foundation/FloatingPointParseStrategy) A parse strategy for creating floating-point values from formatted strings. ### Locating floating-point numbers with regular expressions [`consuming(_:startingAt:in:)`](/documentation/Foundation/FloatingPointFormatStyle/consuming(_:startingAt:in:)) Process the input string within the specified bounds, beginning at the given index, and return the end position (upper bound) of the match and the produced output. ### Supporting types [`Currency`](/documentation/Foundation/FloatingPointFormatStyle/Currency) A format style that converts between floating-point currency values and their textual representations. [`Percent`](/documentation/Foundation/FloatingPointFormatStyle/Percent) A format style that converts between floating-point percentage values and their textual representations. ## Relationships ### Conforms To [`Escapable`](/documentation/Swift/Escapable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`RegexComponent`](/documentation/Swift/RegexComponent) [`Hashable`](/documentation/Swift/Hashable) [`Encodable`](/documentation/Swift/Encodable) [`ParseableFormatStyle`](/documentation/Foundation/ParseableFormatStyle) [`CustomConsumingRegexComponent`](/documentation/Swift/CustomConsumingRegexComponent) [`Sendable`](/documentation/Swift/Sendable) [`FormatStyle`](/documentation/Foundation/FormatStyle) [`Copyable`](/documentation/Swift/Copyable) [`Equatable`](/documentation/Swift/Equatable) [`Decodable`](/documentation/Swift/Decodable) --- Copyright © 2026 Apple Inc. 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