Question

我需要检查单词是否以元音或辅音开头，如下：

let word = "ciao"

if wordStartsWithVowel {
    print("Word starts with Vowel!")
}

我该怎么做？

Answer 1

extension Character {
    var isVowel: Bool { return ["a","e","i","o","u","A","E","I","O","U"].contains(self) }
    var isConsonant: Bool { return ["b","c","d","f","g","h","j","k","l","m","n","p","q","r","s","t","v","w","x","y","z",
                                    "B","C","D","F","G","H","J","K","L","M","N","P","Q","R","S","T","V","W","X","Y","Z"].contains(self) }
}
extension String {
    var startsWithVowel: Bool {
        return characters.first?.isVowel ?? false
    }
    var startsWithConsonant: Bool {
        return characters.first?.isConsonant ?? false
    }
}

let word = "ciao"

print(word.startsWithVowel)      // false
print(word.startsWithConsonant)  // true

或者如果您更喜欢使用NSCharacterSet：

extension Character {
    struct CharacterSet {
        static let vowel    = NSCharacterSet(charactersInString: "aeiouAEIOU")
        static let consonant = NSCharacterSet(charactersInString: "bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ")
    }
    var characterSetValue: NSCharacterSet { return NSCharacterSet(charactersInString: String(self)) }
    var isVowel:     Bool { return CharacterSet.vowel.isSupersetOfSet(characterSetValue) }
    var isConsonant: Bool { return CharacterSet.consonant.isSupersetOfSet(characterSetValue) }
}
"a".characters.first!.isConsonant      // false
"a".characters.first!.isVowel          // true

Answer 2

let vowels: [Character] = ["a","e","i","o","u"]
let word = "ciao"

if vowels.contains(word.lowercased().characters.first!) {
    print("Word starts with Vowel!")
}

.lowercaseString很重要，否则，大写元音不会被识别为元音。

检查单词是否以元音或辅音开头

2 个答案: