与 Mr. Me 类似，这将删除前 6 个字符之前的所有内容，并将它们替换为您的新格式.

Similar to Mr. Me, this will instead remove everything before the first 6 characters and replace them with your new format.

emp_pd["SSN"] = emp_pd["SSN"].apply(lambda x: "***-**" + x[6:])