regular expression

Match symbol ：
d? d appear 0/1 Time
a＊ a Can appear 0/ many times
a+ a More than one occurrence
a｛6｝ a appear 6 Time
a｛2,｝ a appear 2 More than once
a｛2,6｝ a appear 2-6 Time
Match multiple characters ：
(ab)+ ab More than one occurrence
Or operations ：
a (cat|dog) matching a cat or a dog
a cat|dog matching a cat or dog
Character class ：
Match by abc Data of composition 【abc】+ abc More than one occurrence abc aabbcc
【a-zA-Z0-9】 ABCabc123
^ exclude 【^0-9】 matching 0-9 Other data ( Include line breaks )
Metacharacters
\d Numeric character \d+ Match more than one number
\D Nonnumeric character
\w Word characters word Numbers Underscores are English characters
\W Nonword character
\s Blank character Contains spaces and line breaks
\S Nonwhite space character
\b The boundary of words The beginning or end of a word The boundary before words and symbols
\B The boundary of non words Symbols and symbols The boundary between words
. Any character does not contain a newline character
\. Express . adopt \ Made a change of mind
^ Match the beginning of the line $ Match the end of the line
＊+｛｝ Greedy matching
strongbhttps://www.wondershare. com/strong/b
.+ Will match the whole string Because it's a greedy match
.+? Match only two tag codes ,? Set to lazy matching