isAPalindrome.swift

import Foundation

extension String {
	func isAPalindrome() -> Bool {
		var string = self.lowercased()
		let characterSet = Set("abcdefghijklmnopqrstuvwxyz")
		string = string.filter { characterSet.contains($0) }

		return string == String(string.reversed())
	}

	func anotherIsAPalindrome() -> Bool {
		var string = self.lowercased()
		let characterSet = Set("abcdefghijklmnopqrstuvwxyz")
		string = string.filter { characterSet.contains($0) }
		let strArray = Array(string)

		for (index, letter) in strArray.enumerated() {
			if letter != strArray[strArray.count - 1 - index] {
				return false
			}
			if index > strArray.count / 2 {
				break
			}
		}

		return true
	}
}


"tacocat".isAPalindrome()
"never odd or even".isAPalindrome()
"race car".isAPalindrome()
"daily".isAPalindrome()


"tacocat".anotherIsAPalindrome()
"never odd or even".anotherIsAPalindrome()
"race car".anotherIsAPalindrome()
"daily".anotherIsAPalindrome()