\b
Match a word boundary
\w
Match a word character [A-Za-z_]
\W
Match a non-word character
.
Match any character
x*
Match zero or more occurrences of x
x+
Match one or more occurrences of x
x?
Match zero or one occurrences of x
\d
Match a digit character [0-9]
\D
Match a non-digit character
\s
Match a whitespace character
(x)
Create a match group on x
[x]
Create a character class containing x
[^x]
Create a character class excluding x
x{n}
Match x exactly n times
x{n, m}
Match x between n and m times
x{n,}
Match x n or more times