re 模块为高级字符串处理提供了正则表达式工具。对于复杂的匹配和处理，正则表达式提供了简洁、优化的解决方案:

>>> import re
>>> re.findall(r"f[a-z]*", "which foot or hand fell fastest")
["foot", "fell", "fastest"]
>>> re.sub(r"([a-z]+) 1", r"1", "cat in the the hat")
"cat in the hat"

只需简单的操作时，字符串方法最好用，因为它们易读，又容易调试:

>>> "tea for too".replace("too", "two")
"tea for two"