yyyy-mm-dd格式的任意日期
\d\d\d\d-\d\d-\d\d
十六进制字符
[a-fA-F0-9]
[a-fA-F\d]
(?i)[A-F0-9]
非十六进制字符
[^a-fA-F0-9]
(?i)[^A-F0-9]
错误拼写的 calendar
c[ae]l[ae]nd[ae]r
单词边界
\bcat\B
\Bor\b
\Bte\B
\bcategor\b
categor
多个选择分支
Mary|Jane|Sue
Mary, Jane and Sue went to Mary‘s house
是否区分大小写
a(?i)s(?-i)d
aSd
除了换行符之外的任意字符
.
包含换行符在内的任意字符
[\s\S]
[\d\D]
[\w\W]
元字符
\$\(\)\*\+\.\?\[\\\^\{\|
$()*+.?[\^{|
控制字符
\cJ\cM\cI
\x0A\x0D\x09
\n\r\t
