Regular Expressions

MetaCharacter: It is special chacter(s) which have special meaning in Regular Expression.

For Example:
*, ., /, \, ? and ^.

Sr	Meta character	Desctiption
1	[ ]	Match any character within [phc] Means find “p” OR “h” OR “c”
2	-	Range a-z means a to z(a,b,c, ... z) 0-0 means 0 to 9 (0,1,2,3,4,5,6,7,8,9) A-Z means A to Z(A,B,C,D ..... Z)
3	^	Caret It means start with a character For example: ^ab (start with “a”) Inside the bracket if have opposite meaning. For example: [^a](must not start with “a”)
4	$	End with character For Example Abc$ means end with “c”
5	.	The . (period) means any character(s) in this position, For example, ph. will find php, php-tutorial and php-tutorial-php but not aphp because it has no following character
6	?	Matches the preceding character 0 or 1 times only. For example: colou?r will find both color (0 times) and colour (1 time).
7	*	Matches the preceding character 0 or more times. For example: tre* will find tree (2 times) and tread (1 time) and trough (0 times).
8	+	Matches the previous character 1 or more times. For example: tre+ will find tree (2 times) and tread (1 time) but NOT trough (0 times).
9	{n}	Preceding character, or character range, n times exactly. For example: find a local phone number we could use [0-9]{3}-[0-9]{4} which would find any number of the form 723-4567 OR 132-3234 OR 214-3433.
10	()	To group a character. For Example: (php), will find the “php” only.
11	|	Vertical bar used for OR (a|c) find either “a” OR “c”
12	\d	any character in the range 0 – 9
13	\D	Any character not in between 0-9
14	\s	Whitespace or tab
15	\S	Not whitespace or tab
16	\w	Alphanumeric characters (a-z, 0-9, A-Z)
17	\W	Not alphanumeric character (a-z, 0-9, A-Z)