abstract:Portable alpha is the return of an investment portfolio with zero market risk (beta). Being independent of both the direction and the magnitude of the market's movements, it represents the manager's skill in selecting investments.
Youcanuse [: digit:] in place of [0-9], and [: alpha:] isamoreportablereplacement for [-a-za-z0-9_]. For example, you can strip all punctuation from a string by using the statement.
您可以使用[：digit：]代替[0 - 9]，并且[：alpha：]是比[- a - zA - z 0 - 9 _]更具有可移植性的替代者。