POSIX character classes and Java character classes
Character Class Meta-Character Matches \p{Lower} Lowercase letter [a-z] \p{Upper} Uppercase letter [A-Z] \p{ASCII} All ASCII [\x00-\x7F] \p{Alpha} Any lowercase or uppercase letter \p{Digit} A digit [0-9] \p{Alnum} Any letter or digit \p{Punct} Punctuation [!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~] \p{Graph} A visible character: any letter, digit, or punctuation \p{Print} A printable character; same as \p{Graph} \p{Blank} A space or tab [ \t] \p{Cntrl} A control character [\x00-\x1F\x7F] \p{XDigit} Hexadecimal digit [0-9a-fA-F] \p{Space} A whitespace character [ \t\n\x0B\f\r]