String Extensions

Extensions.swift

extension CharacterSet {
    static let vowels = CharacterSet(charactersIn: "aeiou")
    static let consonants = CharacterSet.letters.subtracting(vowels)
}

extension String {
    
    var specialChars: String {
        self
            .components(separatedBy: .punctuationCharacters)
            .joined()
    }
    
    var vowels: String {
        self
            .components(separatedBy: .consonants)
            .joined()
            .filter { $0 != " " }
    }
    
    var consonants: String {
        self
            .components(separatedBy: CharacterSet.vowels)
            .joined()
            .filter { $0 != " " }
    }
    
    // "aaaacciiiiffffpppp".lettersCount
    // => "p4i4c2f4a4"
    var lettersCount: String {
        return self
            .reduce(into: [:]) { (counts, letter) in counts[letter.description, default: 0] += 1 }
            .map { "\($0.key)\($0.value)" }
            .joined()
    }
}

let someString = "first.last.name@email.com"

print(someString.consonants)
// => frst.lst.nm@ml.cm

print(someString.vowels)
// => i.a.ae@eai.o

print(someString.specialChars.consonants)
// => frstlstnmmlcm

print(someString.specialChars.vowels)
// => iaaeeaio