Question

请问正则表达式[0-9_]表示什么意思

When the LOCALE and UNICODE flags are not specified, matches any alphanumeric character and the underscore; this is equivalent to the set [a-zA-Z0-9_]. With LOCALE, it will match the set [0-9_] plus whatever characters are defined as alphanumeric for the current locale. If UNICODE is set, this will match the characters [0-9_] plus whatever is classified as alphanumeric in the Unicode character properties database.

上文摘自https://docs.python.org/2.7/library/re.html 我知道[0-9]表示0到9中的任何一个,但是'_'表示什么?
求解,谢谢.
上文贴的那段话是对\w的解释

Answer 1

[0-9]就是必须有中括号内的0-9任意一个数字。[a-z]就是必须有a-z中任意的字母

追问

额,这个我知道啊.关键后面'_'是什么意思

Answer 2

\w能匹配数字英文下划线 所以解释的话 _ 也在括号里