PartialRangeUpTo

You create PartialRangeUpTo instances by using the prefix half-open range operator (prefix ..<).

let upToFive = ..<5.0

You can use a PartialRangeUpTo instance to quickly check if a value is contained in a particular range of values. For example:

upToFive.contains(3.14)       // true
upToFive.contains(6.28)       // false
upToFive.contains(5.0)        // false

You can use a PartialRangeUpTo instance of a collection’s indices to represent the range from the start of the collection up to, but not including, the partial range’s upper bound.

let numbers = [10, 20, 30, 40, 50, 60, 70]
print(numbers[..<3])
// Prints "[10, 20, 30]"