Generic Instance Method

lexicographicallyPrecedes(_:)

Returns a Boolean value indicating whether the sequence precedes another sequence in a lexicographical (dictionary) ordering, using the less-than operator (<) to compare elements.

Declaration

func lexicographicallyPrecedes<OtherSequence>(_ other: OtherSequence) -> Bool where OtherSequence : Sequence, Self.Element == OtherSequence.Element

Available when Element conforms to Comparable.

Parameters

other: A sequence to compare to this sequence.

Return Value

true if this sequence precedes other in a dictionary ordering; otherwise, false.

Discussion

This example uses the lexicographicallyPrecedes method to test which array of integers comes first in a lexicographical ordering.

let a = [1, 2, 2, 2]
let b = [1, 2, 3, 4]

print(a.lexicographicallyPrecedes(b))
// Prints "true"
print(b.lexicographicallyPrecedes(b))
// Prints "false"

Complexity: O(m), where m is the lesser of the length of the sequence and the length of other.