Regular Expressions are a powerful way to do pattern matching on strings.
Character classes
| Pattern | Description |
|---|
. | Any character, except newline |
\w | Word |
\d | Digit |
\s | Whitespace |
\W | Not word |
\D | Not digit |
\S | Not whitespace |
[abc] | Any of a, b, or c |
[a-e] | Characters between a and e |
[1-9] | Digit between 1 and 9 |
[^abc] | Any character except a, b or c |
Anchors
| Pattern | Description |
|---|
^abc | Start with abc |
abc$ | End with abc |
Escaped characters
| Pattern | Description |
|---|
\. \* \\ | Escape special character used by regex |
\t | Tab |
\n | Newline |
\r | Carriage return |
Groups
| Pattern | Description |
|---|
(abc) | Capture group |
Quantifiers
| Pattern | Description |
|---|
a* | Match 0 or more |
a+ | Match 1 or more |
a? | Match 0 or 1 |
a{5} | Match exactly 5 |
a{,3} | Match up to 3 |
a{3,} | Match 3 or more |
a{1,3} | Match between 1 and 3 |