Tuesday, June 1, 2010

Regular expression single sheet reference

Regular Expression single sheet reference
source : http://networking.ringofsaturn.com/Web/regex.php

want to download in pdf format .. click here





Regular Expressions Reference Sheet

CharacterDefinitionExample
^
The pattern has to appear at the beginning of a string.^cat matches any string that begins with cat
$
The pattern has to appear at the end of a string.cat$ matches any string that ends with cat
.
Matches any character.cat. matches catT and cat2 but not catty
[]
Bracket expression. Matches one of any characters enclosed.gr[ae]y matches gray or grey
[^]
Negates a bracket expression. Matches one of any characters EXCEPT those enclosed.1[^02] matches 13 but not 10 or 12
[-]
Range. Matches any characters within the range.[1-9] matches any single digit EXCEPT 0
?
Preceeding item must match one or zero times.colou?r matches color or colour but not colouur
+
Preceeding item must match one or more times.be+ matches be or bee but not b
*
Preceeding item must match zero or more times.be* matches b or be or beeeeeeeeee
()
Parentheses. Creates a substring or item that metacharacters can be applied toa(bee)?t matches at or abeet but not abet
{n}
Bound. Specifies exact number of times for the preceeding item to match.[0-9]{3} matches any three digits
{n,}
Bound. Specifies minimum number of times for the preceeding item to match.[0-9]{3,} matches any three or more digits
{n,m}
Bound. Specifies minimum and maximum number of times for the preceeding item to match.[0-9]{3,5} matches any three, four, or five digits
|
Alternation. One of the alternatives has to match.July (first|1st|1) will match July 1st but not July 2

POSIX Character Classes

CharacterDefinitionExample
[:alnum:]
alphanumeric character[[:alnum:]]{3} matches any three letters or numbers, like 7Ds
[:alpha:]
alphabetic character, any case[[:alpha:]]{5} matches five alphabetic characters, any case, like aBcDe
[:blank:]
space and tab[[:blank:]]{3,5} matches any three, four, or five spaces and tabs
[:digit:]
digits[[:digit:]]{3,5} matches any three, four, or five digits, like 3, 05, 489
[:lower:]
lowercase alphabetics[[:lower:]] matches a but not A
[:punct:]
punctuation characters[[:punct:]] matches ! or . or , but not a or 3
[:space:]
all whitespace characters, including newline and carriage return[[:space:]] matches any space, tab, newline, or carriage return
[:upper:]
uppercase alphabetics[[:upper:]] matches A but not a

Perl-Style Metacharacters

CharacterDefinitionExample
//
Default delimiters for pattern/colou?r/ matches color or colour
i
Append to pattern to specify a case insensitive match/colou?r/i matches COLOR or Colour
\b
A word boundary, the spot between word (\w) and non-word (\W) characters/\bfred\b/i matches Fred but not Alfred or Frederick
\B
A non-word boundary/fred\B/i matches Frederick but not Fred
\d
A single digit character/a\db/i matches a2b but not acb
\D
A single non-digit character/a\Db/i matches aCb but not a2b
\n
The newline character. (ASCII 10)/\n/ matches a newline
\r
The carriage return character. (ASCII 13)/\r/ matches a carriage return
\s
A single whitespace character/a\sb/ matches a b but not ab
\S
A single non-whitespace character/a\Sb/ matches a2b but not a b
\t
The tab character. (ASCII 9)/\t/ matches a tab.
\w
A single word character - alphanumeric and underscore/\w/ matches 1 or _ but not ?
\W
A single non-word character/a\Wb/i matches a!b but not a2b

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