Regular expression quick start guide

Revision as of 17:36, 26 January 2010 (view source) Lucas Trottier (Talk | contribs) ← Older edit		Revision as of 17:37, 26 January 2010 (view source) Lucas Trottier (Talk | contribs) Newer edit →
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	Special caracters used in regex.		Special caracters used in regex.
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−	=== Metacharacters ===	+	=== Metacharacters ===

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Revision as of 17:37, 26 January 2010

Contents 1 Quick Reference Table 2 Quick References 2.1 Text Patterns and Matches 2.2 Metacharacters 2.3 Literal Characters 2.4 Character Classes or Character Sets 2.5 Shorthand Character Classes 2.6 The Dot Matches (Almost) Any Character 2.7 Repetition 2.8 Optional 2.9 Anchors 2.10 Alternation 2.11 Grouping and Capturing Group 3 Examples 4 Web Online Tools 5 References

Quick Reference Table

Regular Expression Pattern	Explanations	Examples
Metacharacters  [\^$.|?*+(	Special caracters used in regex. Must be escape with backslash "\" to use a literal characters.
Literal characters	All characters (except the metacharacters) match a single instance of themselves. { and } are literal characters, unless they're part of a valid regular expression token (e.g. the {n} quantifier).	/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