61. Reference
• The Unicode Standard
• Unicode Punctuation Characters
• Unicode Emoji Characters
• Unicode Character Categories
• Using character sets in Swift
• Finding Character in CharacterSet - Using Swift - Swift Forums
• 理理解了了Unicode你才能理理解的String與Character
• The Absolute Minimum Every Software Developer Absolutely, Positively Must Know
About Unicode and Character Sets
• 字符串串的 Unicode 表示法
• NSCharacterSet
• SwiftのCharacterSetで⽂文字列列操作 - Qiita
• Three Ways to Enumerate the Words In a String Using Swift
• Natural Language Processing and your Apps