---
title: "units(allowed:width:maximumUnitCount:zeroValueUnits:valueLength:fractionalPart:)"
framework: foundation
role: symbol
role_heading: Type Method
path: "foundation/formatstyle/units(allowed:width:maximumunitcount:zerovalueunits:valuelength:fractionalpart:)"
---

# units(allowed:width:maximumUnitCount:zeroValueUnits:valueLength:fractionalPart:)

Returns a style for formatting a duration that uses the specified units.

## Declaration

```swift
static func units(allowed units: Set<Duration.UnitsFormatStyle.Unit> = [.hours, .minutes, .seconds], width: Duration.UnitsFormatStyle.UnitWidth = .abbreviated, maximumUnitCount: Int? = nil, zeroValueUnits: Duration.UnitsFormatStyle.ZeroValueUnitsDisplayStrategy = .hide, valueLength: Int? = nil, fractionalPart: Duration.UnitsFormatStyle.FractionalPartDisplayStrategy = .hide) -> Self
```

## Parameters

- `units`: The units that the formatted string may include.
- `width`: The width of the unit and the spacing between the value and the unit.
- `maximumUnitCount`: The maximum number of duration units, if any, to include in the output string.
- `zeroValueUnits`: The strategy for handling leading units with zero values.
- `valueLength`: The padding or truncating behavior of the unit value, as an Int. Defaults to nil, which applies no length limit.
- `fractionalPart`: The strategy for displaying a duration if a formatted string can’t represent it exactly with the allowed units.

## Return Value

Return Value A duration units format style that uses the specified units.

## Discussion

Discussion Use the dot-notation form of this type method when the call point allows the use of Duration.UnitsFormatStyle. You typically do this when calling the formatted(_:) method of Duration. The following example creates a duration to represent 1 hour, 10 minutes, 32 seconds, and 400 milliseconds. It then creates a Duration.UnitsFormatStyle to show the hours, minutes, seconds, and milliseconds parts, with a wide width that presents the full name of each unit. let duration = Duration.seconds(70 * 60 + 32) + Duration.milliseconds(400) let formatted = duration.formatted(      .units(allowed: [.hours, .minutes, .seconds, .milliseconds],             width: .wide)) // "1 hour, 10 minutes, 32 seconds, 400 milliseconds"

## See Also

### Applying duration styles

- [timeDuration](foundation/formatstyle/timeduration.md)
- [Date.ComponentsFormatStyle](foundation/date/componentsformatstyle.md)
- [time(pattern:)](foundation/formatstyle/time(pattern:).md)
- [units(allowed:width:maximumUnitCount:zeroValueUnits:valueLengthLimits:fractionalPart:)](foundation/formatstyle/units(allowed:width:maximumunitcount:zerovalueunits:valuelengthlimits:fractionalpart:).md)