Regular expression Notes

One, what can this do?

• Tests the pattern within a string.
  For example, you can test the input string to see if there is a phone number pattern or credit card number pattern within the string. This is called data validation.
• Replace the text.
  You can use regular expressions to identify specific text in a document, to completely delete the text, or to replace it with other text.
• Extracts substrings from a string based on pattern matching.
  You can find specific text within a document or in an input field.
• Special characters:

The The The

	description
$	matches the end position of the input string. If the Multiline property of the RegExp object is set, then $ also matches ' \ n ' or ' \ R '. To match the $ character itself, use \$.
()	marks the start and end positions of a subexpression. Sub-expressions can be obtained for later use. To match these characters, use \ (and \).
*	matches the preceding subexpression 0 or more times. To match the * character, use \*.
+	matches the preceding subexpression one or more times. to match the + character, use \+.
.	matches any single character except for the newline character \ n. To match, please use \.
[	marks the beginning of a bracket expression. to match [, please use \[.
?	matches the preceding subexpression 0 or one time, or indicates a non-greedy qualifier. to match? characters, use \?.
\	marks the next character as either a special character, or a literal character, or a backward reference, or octal escape character. For example, ' n ' matches the character ' n '. ' \ n ' matches line breaks. The sequence ' \ \ ' matches ' \ ', while ' \ (' then Match ' (".
^	matches the starting position of the input string, unless used in a square bracket expression, which indicates that the character set is not accepted. To match the ^ character itself, use \^.
{	tags the beginning of the qualifier expression. To match {, use \{.
|	indicates a choice between the two items. to match |, please use \|.

Qualifier:

character	Description
*	Matches the preceding subexpression 0 or more times. For example, zo* can match "z" and "Zoo". * Equivalent to {0,}.
+	Matches the preceding subexpression one or more times. For example, ' zo+ ' can match "Zo" and "Zoo", but not "Z". + equivalent to {1,}.
?	Matches the preceding subexpression 0 or one time. For example, "Do (es)?" can match "do" in "do" or "does".? 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}	Both M and n are non-negative integers, where n <= m. Matches at least n times and matches up to M times. For example, "o{1,3}" will match the first three o in "Fooooood". ' o{0,1} ' is equivalent to ' O? '. Note that there can be no spaces between a comma and two numbers.

Locator:

character	Description
^	Matches the starting position of the input string. If you set the Multiline property of the RegExp object, ^ will also match the position after \ n or \ r.
$	Matches the position of the end of the input string. If you set the Multiline property of the RegExp object, the $ will also match the position before \ n or \ r.
\b	Matches a word boundary, which is the position between the word and the space.
\b	Non-word boundary match.

Metacharacters

character	Description
\	Marks the next character as a special character, or a literal character, or a backward reference, or an octal escape. For example, ' n ' matches the character "n". ' \ n ' matches a line break. The sequence ' \ \ ' matches "\" and "\ (" Matches "(".
^	Matches the starting 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, $ also matches the position before ' \ n ' or ' \ R '.
*	Matches the preceding subexpression 0 or more times. For example, zo* can match "z" and "Zoo". * Equivalent to {0,}.
+	Matches the preceding subexpression one or more times. For example, ' zo+ ' can match "Zo" and "Zoo", but not "Z". + equivalent to {1,}.
?	Matches the preceding subexpression 0 or one time. For example, "Do (es)?" can match "do" in "do" or "does".? 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}	Both M and n are non-negative integers, where n <= m. Matches at least n times and matches up to M times. For example, "o{1,3}" will match the first three o in "Fooooood". ' o{0,1} ' is equivalent to ' O? '. Note that there can be no spaces between a comma and two numbers.
?	When the character immediately follows any other restriction (*, +,?, {n}, {n,}, {n,m}), the matching pattern is non-greedy. The non-greedy pattern matches the searched string as little 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", while ' 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, the Submatches collection is used in VBScript, and the $0...$9 property is used in JScript. To match the parentheses character, use ' \ (' or ' \ ').
(?:p Attern)	Matches pattern but does not get a matching result, which means that this is a non-fetch match and is not stored for later use. This is useful when using the "or" character (|) to combine parts of a pattern. For example, ' Industr (?: y|ies) is a more abbreviated expression than ' industry|industries '.
(? =pattern)	Forward-checking matches the lookup string at the beginning of any string that matches the pattern. This is a non-fetch match, which means that the match does not need to be acquired for later use. For example, ' Windows (? =95|98| nt|2000) ' Can match Windows 2000 ', but does not match Windows 3.1 in Windows. Pre-checking does not consume characters, that is, after a match occurs, the next matching search starts immediately after the last match, rather than starting with the character that contains the pre-check.
(?! Pattern	A negative pre-check matches the lookup string at the beginning of any string that does not match the pattern. This is a non-fetch match, which means that the match does not need to be acquired for later use. For example ' Windows (?! 95|98| nt|2000) ' can match Windows 3.1 ', but does not match Windows 2000 in Windows. Pre-checking does not consume characters, that is, after a match occurs, the next matching search starts immediately after the last match, rather than starting with 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]	The character set is combined. Matches any one of the characters contained. For example, ' [ABC] ' can match ' a ' in ' plain '.
[^XYZ]	Negative character set. Matches any character that is not contained. For example, ' [^ABC] ' can match ' P ', ' l ', ' I ', ' n ' in ' plain '.
[A-z]	The character range. Matches any character within the specified range. For example, ' [A-z] ' can match any lowercase alphabetic character in the ' a ' to ' Z ' range.
[^a-z]	A negative character range. Matches any character that is not in the specified range. For example, ' [^a-z] ' can match any character that is not within the range of ' a ' to ' Z '.
\b	Matches a word boundary, which is the position between a word and a space. For example, ' er\b ' can match ' er ' in ' never ', but not ' 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. The value of x must be one of 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 break. Equivalent to \x0c and \CL.
\ n	Matches a line break. Equivalent to \x0a and \CJ.
\ r	Matches a carriage return character. Equivalent to \x0d and \cm.
\s	Matches any whitespace character, including spaces, tabs, page breaks, and so on. equivalent to [\f\n\r\t\v].
\s	Matches any non-whitespace 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	Match N, where n is the hexadecimal escape value. The hexadecimal escape value must be two digits long for a determination. For example, ' \x41 ' matches ' A '. ' \x041 ' is equivalent to ' \x04 ' & ' 1 '. ASCII encoding can be used in regular expressions.
\num	Matches num, where num is a positive integer. A reference to the obtained match. For example, ' (.) \1 ' matches two consecutive identical characters.
\ n	Identifies an octal escape value or a backward reference. n is a backward reference if \ n is preceded by at least one of the sub-expressions obtained. Otherwise, if n is the octal number (0-7), N is an octal escape value.
\nm	Identifies an octal escape value or a backward reference. If at least NM has obtained a subexpression before \nm, then NM is a backward reference. If there are at least N fetches before \nm, then n is a backward reference followed by the literal m. If none of the preceding conditions are met, if both N and M are octal digits (0-7), then \nm will match the 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	Match N, where N is a Unicode character represented by four hexadecimal digits. For example, \u00a9 matches the copyright symbol (?).

Above from rookie tutorial

Second, JS and regular

The introduction from the Scripting House benefited

Http://www.jb51.net/article/88838.htm

Second, remarks

1. Regular note When using some special characters, be aware of escaping

2. This small point is commonly used. matches any single character except the newline character \ n. To match, please use \.

3. Through the *, + or? After the qualifier is placed, the expression is converted from a "greedy" expression to a "non-greedy" expression or a minimum match.

4.[A-Z] This type of character cluster can only represent one character

Regular expression Notes