[C #] about regular expressions

Regular

\
Marks the next character as a special character, or a literal character, or a back reference, or a octal escape character. For example, ' n ' matches the character ' n '. ' \ n ' matches a newline character. Sequence ' \ ' matches ' \ ' and ' \ (' Matches ' (".

^
Matches the start position of the input string. If the Multiline property of the RegExp object is set, ^ also matches the position after ' \ n ' or ' \ R '.

$
Matches the end position of the input string. If the Multiline property of the RegExp object is set, the $ also matches the position before ' \ n ' or ' \ R '.

*
Matches the preceding subexpression 0 or more times. For example, zo* can match "z" and "Zoo". * is equivalent to {0,}.

+
Matches the preceding subexpression one or more times. For example, ' zo+ ' can match "Zo" and "Zoo", but cannot match "Z". + is equivalent to {1,}.

?
Match the preceding subexpression 0 times or once. For example, "Do (es)" can match "do" in "do" or "does". is equivalent to {0,1}.

{n}
n is a non-negative integer. Matches the determined n times. For example, ' o{2} ' cannot match ' o ' in ' Bob ', but can match two o in ' food '.

{n,}
n is a non-negative integer. Match at least n times. For example, ' o{2,} ' cannot match ' o ' in ' Bob ' but can match all o in ' Foooood '. ' O{1,} ' is equivalent to ' o+ '. ' O{0,} ' is equivalent to ' o* '.

{n,m}
M and n are nonnegative integers, of which n <= M. Matches n times at least and matches up to M times. "o{1,3}" will match the first three o in "Fooooood". ' o{0,1} ' is equivalent to ' o '. Notice that there is no space between the comma and the two number.

?
When the character is immediately following any of the other qualifiers (*, +,?, {n}, {n,}, {n,m}), the matching pattern is not greedy. Non-greedy patterns match as few strings as possible, while the default greedy pattern matches as many of the searched strings as possible. For example, for the string "oooo", ' o+? ' will match a single "O", and ' o+ ' will match all ' o '.

.
Matches any single character except "\ n". To match any character including ' \ n ', use a pattern like ' [. \ n] '.

(pattern)
Match pattern and get this match. The obtained matches can be obtained from the resulting matches collection, use the Submatches collection in VBScript, and use the $0...$9 property in visual Basic scripting Edition. To match the parentheses character, use ' \ (' or ' \ ').

(?:p attern)
Matches pattern but does not get a matching result, which means it is a non fetch match and is not stored for later use. This is useful for combining parts of a pattern with the "or" character (|). For example, ' Industr (?: y|ies) is a more abbreviated expression than ' industry|industries '.

(? =pattern)
Forward lookup, matching the find string at the beginning of any string matching pattern. This is a non-fetch match, that is, the match does not need to be acquired for later use. For example, ' Windows (? =95|98| nt|2000) ' Can match windows in Windows 2000, but cannot match windows in Windows 3.1. It does not consume characters, that is, after a match occurs, the next matching search begins immediately after the last match, instead of starting after the character that contains the pre-check.

(?! Pattern
A negative check matches the lookup string at the beginning of any mismatched negative lookahead matches the search string at either point where a string is not matching. This is a non-fetch match, that is, the match does not need to be acquired for later use. For example, ' Windows (?! 95|98| nt|2000) ' Can match windows in Windows 3.1, but cannot match windows in Windows 2000. It does not consume characters, that is, after a match occurs, the next matching search begins immediately after the last match, instead of starting after the character that contains the pre-check.

X|y
Match x or Y. For example, ' Z|food ' can match "z" or "food". ' (z|f) Ood ' matches ' zood ' or ' food '.

[XYZ]
Character set combination. Matches any one of the characters contained. For example, ' [ABC] ' can match ' a ' in ' plain '.

[^XYZ]
Negative character set combination. Matches any characters that are not included. For example, ' [^ABC] ' can match ' P ' in ' plain '.

[A-z]
The range of characters. Matches any character within the specified range. For example, ' [A-z] ' can match any lowercase alphabetic character in the range ' a ' to ' Z '.

[^a-z]
Negative character range. Matches any character that is not in the specified range. For example, ' [^a-z] ' can match any character that is not in the range of ' a ' to ' Z '.

\b
Matches a word boundary, which is the position between the word and the space. For example, ' er\b ' can match ' er ' in ' never ', but cannot match ' er ' in ' verb '.

\b
Matches a non-word boundary. ' er\b ' can match ' er ' in ' verb ', but cannot match ' er ' in ' Never '.

\CX
Matches the control character indicated by X. For example, \cm matches a control-m or carriage return character. The value of x must be one-a-Z or a-Z. Otherwise, c is treated as a literal ' C ' character.

\d
Matches a numeric character. equivalent to [0-9].

\d
Matches a non-numeric character. equivalent to [^0-9].

\f
Matches a page feed character. Equivalent to \x0c and \CL.

\ n
Matches a line feed character. Equivalent to \x0a and \CJ.

\ r
Matches a carriage return character. Equivalent to \x0d and \cm.

\s
Matches any white space character, including spaces, tabs, page breaks, and so on. equivalent to [\f\n\r\t\v].

\s
Matches any non-white-space character. equivalent to [^ \f\n\r\t\v].

\ t
Matches a tab character. Equivalent to \x09 and \ci.

\v
Matches a vertical tab. Equivalent to \x0b and \ck.

\w
Matches any word character that includes an underscore. Equivalent to ' [a-za-z0-9_] '.

\w
Matches any non word character. Equivalent to ' [^a-za-z0-9_] '.

\XN
Matches n, where n is the hexadecimal escape value. The hexadecimal escape value must be a determined two digits long. For example, ' \x41 ' matches ' A '. ' \x041 ' is equivalent to ' \x04 ' & ' 1 '. You can use ASCII encoding in regular expressions ...

\num
Matches num, where num is a positive integer. A reference to the match that was obtained. For example, ' (.) \1 ' matches two consecutive identical characters.

\ n
Identifies a octal escape value or a back reference. N is a back reference if you have at least N obtained subexpression before. Otherwise, if n is an octal number (0-7), then N is an octal escape value.

\nm
Identifies a octal escape value or a back reference. NM is a \nm if at least one of the preceded by the at least NM gets the subexpression before the If there are at least N fetches before \nm, then N is a back reference followed by a literal m. If all the preceding conditions are not satisfied, if both N and M are octal digits (0-7), then \nm will match octal escape value nm.

\NML
If n is an octal number (0-3) and both M and L are octal digits (0-7), the octal escape value NML is matched.

\un
Matches n, where N is a Unicode character represented in four hexadecimal digits. For example, \u00a9 matches the copyright symbol (?).