---
title: "...(_:)"
framework: swift
role: symbol
role_heading: Operator
path: "swift/taskpriority/'...(_:)-79mxl"
---

# ...(_:)

Returns a partial range up to, and including, its upper bound.

## Declaration

```swift
static func ... (maximum: Self) -> PartialRangeThrough<Self>
```

## Parameters

- `maximum`: The upper bound for the range.

## Discussion

Discussion Use the prefix closed range operator (prefix ...) to create a partial range of any type that conforms to the Comparable protocol. This example creates a PartialRangeThrough<Double> instance that includes any value less than or equal to 5.0. let throughFive = ...5.0

throughFive.contains(4.0)     // true throughFive.contains(5.0)     // true throughFive.contains(6.0)     // false You can use this type of partial range of a collection’s indices to represent the range from the start of the collection up to, and including, the partial range’s upper bound. let numbers = [10, 20, 30, 40, 50, 60, 70] print(numbers[...3]) // Prints "[10, 20, 30, 40]" note: maximum must compare equal to itself (i.e. cannot be NaN).