swift 汉字转拼音

extension String {

    func transformToPinYin() -> String {

        let mutableString = NSMutableString(string: self)
        //把汉字转为拼音
        CFStringTransform(mutableString, nil, kCFStringTransformToLatin, false)
        //去掉拼音的音标
        CFStringTransform(mutableString, nil, kCFStringTransformStripDiacritics, false)

        let string = String(mutableString)
        //去掉空格
        return string.stringByReplacingOccurrencesOfString(" ", withString: "")
    }
}