An extension for String to detect if it contains Chinese characters

String+ChineseDetect.swift

extension String {
    var containsChinese: Bool {
        for substring in self {
            if substring.isChinese {
                return true
            }
        }
        return false
    }
}

extension Character {
    var isChinese: Bool {
        if ("\u{4E00}" <= self  && self <= "\u{9FA5}") {
            return true
        } else {
            return false
        }
    }
}