Regular expression quick start guide
From TBwiki
(Difference between revisions)
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! align="left" | Examples<br> | ! align="left" | Examples<br> | ||
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| − | | [\^$.|?*+(<br> | + | | [\^$.|?*+(<br> |
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| − | Special caracters used in regex. | + | Special caracters used in regex. |
*Must be escape with backslash "\" to use a literal characters. | *Must be escape with backslash "\" to use a literal characters. | ||
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|- | |- | ||
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| − | Literal characters<br> | + | Literal characters<br> |
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| − | All characters (except the metacharacters) match a single instance of themselves. <br> | + | All characters (except the metacharacters) match a single instance of themselves. <br> |
*{ and } are literal characters, unless they're part of a valid regular expression token (e.g. the {n} quantifier). | *{ and } are literal characters, unless they're part of a valid regular expression token (e.g. the {n} quantifier). | ||
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| ''/a/'' matches "a"<br> | | ''/a/'' matches "a"<br> | ||
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| − | | <br> | + | | <br> |
| − | | <br> | + | | <br> |
| <br> | | <br> | ||
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=== Metacharacters === | === Metacharacters === | ||
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=== Literal Characters<br> === | === Literal Characters<br> === | ||
Revision as of 17:36, 26 January 2010
Contents |
Quick Reference Table
| Regular Expression Pattern | Explanations | Examples |
|---|---|---|
| [\^$.|?*+( |
Special caracters used in regex.
|
|
|
Literal characters |
All characters (except the metacharacters) match a single instance of themselves.
|
/a/ matches "a" |
| |
|
|
| ^ | Matches beginning of a line | |
| $ | Matches the end of a line | |
| \d | Matches a digit | |
| [characters] | Matches any single character between the brackets | |
| re1|re2 | Match either re1 or re2 | |
| re* | Matches zero or more occurrences of re | |
| re+ | Matches one or more occurrences of re | |
| re? | Matches zero or one occurrences of re | |
| Re{m,n} | Matches at least “m” and at most “n” occurrences of re | |
| (...) | Parentheses are used to group regular expressions | |
| \0, \1, \2, ... | Substitute the value matched by the nth grouped sub-expression, used in remapped fields. | |
Quick References
Text Patterns and Matches
Metacharacters
Literal Characters
Character Classes or Character Sets
Shorthand Character Classes
The Dot Matches (Almost) Any Character
Repetition
Optional
Anchors
Alternation
Grouping and Capturing Group
Examples
Here are some examples:
Add 2720 prefix:
/(\d+)/2720\1/
or
/([0-9]*)/2720\1/
Strip first 4 digits:
/([0-9]{4})([0-9]*)/\2/
Strip # and 7 first digits:
/([#])([0-9]{7})([0-9]*)/\3/
Web Online Tools
- Regular builder tool : www.gskinner.com/RegExr
- Ruby regular expression editor and tester : rubular.com
References
- How to Use RegEx in Called and Calling Number Mask
- How to Use RegEx in Remapped Called and Calling Number Mask
