我对你的措辞感到有些困惑。在我看来，你的表达式会匹配a或b的任意组合，因此在我看来，使用 [ab] * 会更容易阅读。

I'm a little confused by your wording.  It looks to me like your expression would match any combination of a or b, so using [ab]* would be easier to read in my opinion.