Regular Expression - C#

Metacharacter	Description
.	Find a single character, except newline or line terminator
\w	Find a word character
\W	Find a non-word character
\d	Find a digit
\D	Find a non-digit character
\s	Find a whitespace character
\S	Find a non-whitespace character
\b	Find a match at the beginning/end of a word
\B	Find a match not at the beginning/end of a word
\0	Find a NUL character
\n	Find a new line character

Pattern	Description
^	Start at the beginning of the string.
\s*	Match zero or more white-space characters.
[\+-]?	Match zero or one occurrence of either the positive sign or the negative sign.
\s?	Match zero or one white-space character.
\$?	Match zero or one occurrence of the dollar sign.
\s?	Match zero or one white-space character.
\d*	Match zero or more decimal digits.
\.?	Match zero or one decimal point symbol.
\d{2}?	Match two decimal digits zero or one time.
(\d*\.?\d{2}?){1}	Match the pattern of integral and fractional digits separated by a decimal point symbol at least one time.
$	Match the end of the string.

Quantifier	Description
n+	Matches any string that contains at least one n
n*	Matches any string that contains zero or more occurrences of n
n?	Matches any string that contains zero or one occurrences of n
n{X}	Matches any string that contains a sequence of X n's
n{X,Y}	Matches any string that contains a sequence of X to Y n's
n{X,}	Matches any string that contains a sequence of at least X n's
n$	Matches any string with n at the end of it
^n	Matches any string with n at the beginning of it
?=n	Matches any string that is followed by a specific string n
?!n	Matches any string that is not followed by a specific string n

Expression	Description
[abc]	Find any character between the brackets
[^abc]	Find any character NOT between the brackets
[0-9]	Find any character between the brackets (any digit)
[^0-9]	Find any character NOT between the brackets (any non-digit)
(x|y)	Find any of the alternatives specified (X or Y)
{3}	Lengh of 3
{3,6}	Length between 3 to 6
[0-9A-Z]	Match an alphanumeric character. The part number must consist of at least this character.
[-.\w]*	Match zero or more occurrences of any word character, hyphen, or period.
\$	Match a dollar sign.
(?<=[0-9A-Z])	Look ahead of the ending dollar sign to ensure that the previous character is alphanumeric.
[.?:;!]	Match a period, question mark, colon, semicolon, or exclamation point.

Example	Pattern
Email	^([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$
WebSite	^http(s)?://([\w-]+.)+[\w-]+(/[\w- ./?%&=])?$
Password	^(?=.*[A-Z].*[A-Z])(?=.*[!@#$&*])(?=.*[0-9].*[0-9])(?=.*[a-z].*[a-z].*[a-z]).{8}$

Cheat Code
Character	Description
\	Marks the next character as either a special character or escapes a literal. For example, "n" matches the character "n". "\n" matches a newline character. The sequence "\\" matches "\" and "\(" matches "(".
	Note: double quotes may be escaped by doubling them: "<a href=""...>"
^	Depending on whether the MultiLine option is set, matches the position before the first character in a line, or the first character in the string.
$	Depending on whether the MultiLine option is set, matches the position after the last character in a line, or the last character in the string.
*	Matches the preceding character zero or more times. For example, "zo*" matches either "z" or "zoo".
+	Matches the preceding character one or more times. For example, "zo+" matches "zoo" but not "z".
?	Matches the preceding character zero or one time. For example, "a?ve?" matches the "ve" in "never".
.	Matches any single character except a newline character.
(pattern)	Matches pattern and remembers the match. The matched substring can be retrieved from the resulting Matches collection, using Item [0]...[n]. To match parentheses characters ( ), use "\(" or "\)".
(?<name>pattern)	Matches pattern and gives the match a name.
(?:pattern)	A non-capturing group
(?=...)	A positive lookahead
(?!...)	A negative lookahead
(?<=...)	A positive lookbehind .
(?<!...)	A negative lookbehind .
x|y	Matches either x or y. For example, "z|wood" matches "z" or "wood". "(z|w)oo" matches "zoo" or "wood".
{n}	n is a non-negative integer. Matches exactly n times. For example, "o{2}" does not match the "o" in "Bob," but matches the first two o's in "foooood".
{n,}	n is a non-negative integer. Matches at least n times. For example, "o{2,}" does not match the "o" in "Bob" and matches all the o's in "foooood." "o{1,}" is equivalent to "o+". "o{0,}" is equivalent to "o*".
{n,m}	m and n are non-negative integers. Matches at least n and at most m times. For example, "o{1,3}" matches the first three o's in "fooooood." "o{0,1}" is equivalent to "o?".
[xyz]	A character set. Matches any one of the enclosed characters. For example, "[abc]" matches the "a" in "plain".
[^xyz]	A negative character set. Matches any character not enclosed. For example, "[^abc]" matches the "p" in "plain".
[a-z]	A range of characters. Matches any character in the specified range. For example, "[a-z]" matches any lowercase alphabetic character in the range "a" through "z".
[^m-z]	A negative range characters. Matches any character not in the specified range. For example, "[m-z]" matches any character not in the range "m" through "z".
\b	Matches a word boundary, that is, the position between a word and a space. For example, "er\b" matches the "er" in "never" but not the "er" in "verb".
\B	Matches a non-word boundary. "ea*r\B" matches the "ear" in "never early".
\d	Matches a digit character. Equivalent to [0-9].
\D	Matches a non-digit character. Equivalent to [^0-9].
\f	Matches a form-feed character.
\k	A back-reference to a named group.
\n	Matches a newline character.
\r	Matches a carriage return character.
\s	Matches any white space including space, tab, form-feed, etc. Equivalent to "[ \f\n\r\t\v]".
\S	Matches any nonwhite space character. Equivalent to "[^ \f\n\r\t\v]".
\t	Matches a tab character.
\v	Matches a vertical tab character.
\w	Matches any word character including underscore. Equivalent to "[A-Za-z0-9_]".
\W	Matches any non-word character. Equivalent to "[^A-Za-z0-9_]".
\num	Matches num, where num is a positive integer. A reference back to remembered matches. For example, "(.)\1" matches two consecutive identical characters.
\n	Matches n, where n is an octal escape value. Octal escape values must be 1, 2, or 3 digits long. For example, "\11" and "\011" both match a tab character. "\0011" is the equivalent of "\001" & "1". Octal escape values must not exceed 256. If they do, only the first two digits comprise the expression. Allows ASCII codes to be used in regular expressions.
\xn	Matches n, where n is a hexadecimal escape value. Hexadecimal escape values must be exactly two digits long. For example, "\x41" matches "A". "\x041" is equivalent to "\x04" & "1". Allows ASCII codes to be used in regular expressions.
\un	Matches a Unicode character expressed in hexadecimal notation with exactly four numeric digits. "\u0200" matches a space character.
\A	Matches the position before the first character in a string. Not affected by the MultiLine setting
\Z	Matches the position after the last character of a string. Not affected by the MultiLine setting.
\G	Specifies that the matches must be consecutive, without any intervening non-matching characters.

Regular Expression Test