| . | Any character except newline |
| \\d | Digit [0-9] |
| \\w | Word character [a-zA-Z0-9_] |
| \\s | Whitespace |
| \\b | Word boundary |
| ^ | Start of string |
| $ | End of string |
| * | 0 or more |
| + | 1 or more |
| ? | 0 or 1 (optional) |
| {n,m} | Between n and m times |
| [abc] | Character class |
| (abc) | Capture group |
| (?:abc) | Non-capture group |
| a|b | Alternation (or) |
| (?=a) | Positive lookahead |
| (?!a) | Negative lookahead |