1. 需求及方法

1) Calendar with misspellings

c[ae]l[ae]nd[ae]r

2) Hexadecimal character

[a-fA-F0-9]

3) Non-hexadecimal character

[^a-fA-F0-9]

2. 小结

1). Shorthand character

\d matches a single digit

\D matches any character that is not a digit

\w matches a single word character

\W matches a character that is not part of such a propellerhead word

\s matches any whitespace character (including spaces,tabs,line breaks)

\S matches any character not matched by <\s>

2). Case insensitivity

(?i)

eg. (?i)[A-F0-9]