Digit
regex
2 alternatives
\d
a or b
regex
(a|b)
Group
regex
(...)
Range (a or b or c)
regex
[abc]
Not (a or b or c)
[^abc]
Lower case letter from a to q
[a-q]
Upper case letter from A to Q
[A-Q]
Digit from 0 to 7
[0-7]
Look-ahead assertions
?=
Negative look-ahead
?!
Look-behind assertion
?<=
Negative look-behind
?!=
?<!
Any character except new line
.
0 or more
*
1 or more
+
Exactly 3
{3}
3 or more
{3,}
3, 4, or 5
{3-5}
Not digit
\D
Word
\w
Not word
\W
White space
\s
Not white space
\S
Start of string or line