| [abc] |
A single character of: a, b, or c |
| [^abc] |
Any single character except: a, b, or c |
| [a-z] |
Any single character in the range a-z |
| [a-zA-Z] |
Any single char in the range a-z or A-Z |
| (…) |
Capture everything enclosed |
| (a|b) |
a or b |
| a? |
Zero or one of a (lazy) |
| a* |
Zero or more of a (greedy) |
| a+ |
One or more of a |
| a{3} |
Exactly 3 of a |
| a{3,} |
3 or more of a |
| a{3,6} |
Between 3 and 6 of a |
| ^ |
Start of line |
| $ |
End of line |
| \A |
Start of string |
| \z |
End of string |
| . |
Any single character |
| \s |
Any whitespace character |
| \S |
Any non-whitespace character |
| \d |
Any digit |
| \D |
Any non-digit |
| \w |
Any word character (letter, number, underscore) |
| \W |
Any non-word character |
| \b |
Any word boundary |