Swift 判断字符串有多少汉字

let str = "abc积分换地方叫对方吧由11234"
func hanziCount(str: String) -> Int {
    var count = 0
    for c in str where ("\u{4E00}" <= c  && c <= "\u{9FA5}") {
        count += 1
    }
    return count
}
print(hanziCount(str: str))