Instance MethodSwift
starts(with:)
Returns a Boolean value indicating whether the initial elements of the sequence are the same as the elements in another sequence.
func starts<PossiblePrefix>(with possiblePrefix: PossiblePrefix) -> Bool where PossiblePrefix : Sequence, Self.Element == PossiblePrefix.ElementParameters
- possiblePrefix
A sequence to compare to this sequence.
Returns
true if the initial elements of the sequence are the same as the elements of possiblePrefix; otherwise, false. If possiblePrefix has no elements, the return value is true.
Overview
This example tests whether one countable range begins with the elements of another countable range.
let a = 1...3
let b = 1...10
print(b.starts(with: a))
// Prints "true"Passing a sequence with no elements or an empty collection as possiblePrefix always results in true.
print(b.starts(with: []))
// Prints "true"