| Regular Expression Basics |
|---|
| . | Any character except newline |
| a | The character a |
| ab | The string ab |
| a|b | a or b |
| a* | 0 or more a's |
| \ | Escapes a special character |
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| Regular Expression Quantifiers |
|---|
| * | 0 or more |
| + | 1 or more |
| ? | 0 or 1 |
| {2} | Exactly 2 |
| {2, 5} | Between 2 and 5 |
| {2,} | 2 or more |
| Default is greedy. Append ? for reluctant. |
| Regular Expression Groups |
|---|
| (...) | Capturing group |
| (?:...) | Non-capturing group |
| \Y | Match the Y'th captured group |
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| Regular Expression Character Classes |
|---|
| [ab-d] | One character of: a, b, c, d |
| [^ab-d] | One character except: a, b, c, d |
| [\b] | Backspace character |
| \d | One digit |
| \D | One non-digit |
| \s | One whitespace |
| \S | One non-whitespace |
| \w | One word character |
| \W | One non-word character |
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| Regular Expression Assertions |
|---|
| ^ | Start of string |
| $ | End of string |
| \b | Word boundary |
| \B | Non-word boundary |
| (?=...) | Positive lookahead |
| (?!...) | Negative lookahead |
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| Regular Expression Flags |
|---|
| g | Global Match |
| i | Ignore case |
| m | ^ and $ match start and end of line |
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| Regular Expression Special Characters |
|---|
| \n | Newline |
| \r | Carriage return |
| \t | Tab |
| \0 | Null character |
| \YYY | Octal character YYY |
| \xYY | Hexadecimal character YY |
| \uYYYY | Hexadecimal character YYYY |
| \cY | Control character Y |
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| Regular Expression Posix Classes |
|---|
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| Regular Expression Replacement |
|---|
| $$ | Inserts $ |
| $& | Insert entire match |
| $` | Insert preceding string |
| $' | Insert following string |
| $Y | Insert Y'th captured group |
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