混淆正则表达式问题规则 [英] Confusion Regular expression problems rules

问题描述

由于互联网上正则表达式的例子很少..我对正则表达式有很多困惑.

[ab]正则表达式是什么意思

它是a，b还是类似a，b，aa，bb，aaa，bbb ............
和

[0-9]仅是0、1、2、3、4、5、6、7、8、9吗?或0,1,2,3,4,5,6,7,8,9，10,11,12 ....

正则表达式中的^和$是什么意思?

Due to so much less examples of regular expression on internet.. i have lots of confusion in regular expression.

[ab] what is the meaning of it in regular expression

it it a,b or its like a,b,aa,bb,aaa,bbb............
and

[0-9] is it like 0,1,2,3,4,5,6,7,8,9 only ?? or 0,1,2,3,4,5,6,7,8,9 ,10,11,12....

and what is the meaning of ^ and $ in regular expression??

推荐答案

正则表达式中?

您的困惑是当然.让我设法消除您的困惑.

[..]:-表示它具有要匹配的显式字符集.
^:-表示字符串的开头.

your confusion are for sure. let me try to remove your confusion.

[..] :- it means it has explicit set of character to match.
^ :- it means start of string.

:-表示字符串的结尾.
还有更多类似的内容-
\:-在上方或下方之一之前.
. :-除换行符(\ n)外的任何字符.
| :-交替.

:- it means end of string.
there are more like--
\ :- preceding one of the above or down.
. :- any character except new line(\n).
| :- alternation.

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