检查 String 是否包含定义集中的字符

快报

Version = 3.0

let letters = CharacterSet.letters

let phrase = "Test case"
let range = phrase.rangeOfCharacter(from: letters)

// range will be nil if no letters is found
if let test = range {
   print("letters found")
}
else {
   print("letters not found")
}

Version = 2.2

let letters = NSCharacterSet.letterCharacterSet()

let phrase = "Test case"
let range = phrase.rangeOfCharacterFromSet(letters)

// range will be nil if no letters is found
if let test = range {
   print("letters found")
}
else {
  print("letters not found")
}

同时桥接到 Objective-C NSCharacterSet 类的新 CharacterSet 结构定义了几个预定义集：

• decimalDigits
• capitalizedLetters
• alphanumerics
• controlCharacters
• illegalCharacters
• 你可以在 NSCharacterSet 参考中找到更多内容。

你还可以定义自己的字符集：

Version = 3.0

let phrase = "Test case"
let charset = CharacterSet(charactersIn: "t")

if let _ = phrase.rangeOfCharacter(from: charset, options: .caseInsensitive) {
   print("yes") 
}
else {
   print("no")
}

Version = 2.2

let charset = NSCharacterSet(charactersInString: "t")

if let _ = phrase.rangeOfCharacterFromSet(charset, options: .CaseInsensitiveSearch, range: nil) {
   print("yes")
}
else {
    print("no")
}

你还可以包括范围：

Version = 3.0

let phrase = "Test case"
let charset = CharacterSet(charactersIn: "t")

if let _ = phrase.rangeOfCharacter(from: charset, options: .caseInsensitive, range: phrase.startIndex..<phrase.endIndex)) {
   print("yes") 
}
else {
   print("no")
}