Determine if a character is a vowel or not

vowels.swift

extension Character {
    var isVowel: Bool {
        let vowels: [Character] = ["a", "e", "i", "o", "u"]
        return vowels.contains(self)
    }
}

I added the uppercased versions to the Character Extension, as well as an isConsonant that just piggy backs off of isVowel so you don't have to loop through all the other characters.

extension Character {
    var isVowel: Bool {
        let vowels: [Character] = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"]
        return vowels.contains(self)
    }
    var isConsonant: Bool {
        return !self.isVowel
    }
}

func removeVowels(from string: String) -> String {
    var result: String = ""
    for character: Character in string.characters {
        if character.isConsonant {
            result.append(character)
        }
    }
    return result
}

'characters' is deprecated in the newer versions of swift thus removeVowels function should:

func removeVowels(from value: String) -> String {
  return String(value.filter { !["a", "e", "i", "o", "u"].contains($0) })
}

extension Character
{
    var isVowel: Bool {
        return "aeiou".contains(self)
    }
}

func removeVowels(from: String) -> String
{
    return from.filter { !$0.isVowel }
}

func removeVowels(from mystring: String) -> String {
    let vowels:[Character] = ["a","e","i","o","u","y"]
    var output = ""
    for a in mystring {
        if vowels.contains(a) != true {
            output += String(a)
        }
    }
    return output
 }

func removeVowels(from value: String) -> String {
    var vowels: [Character] = ["a", "e", "i", "o", "u"]
    
    var newValue = value.lowercased()
    
    newValue.removeAll(where: { vowels.contains($0) })

    return newValue
}