Special character meanings of regular expressions

Today, I see a good article about regular expressions, which is about the special character meaning of regular expressions, and it feels very good, so record it.

Characters

Meaning: For a character, it is usually expressed as literal meaning that the next character is a special character.
For example:/b/matches the character ' B ', by adding a backslash in front of B, or/b/, the character becomes a special character that represents the dividing line of a word. Or: For a few characters, the usual description is special, indicating that the characters immediately followed are not special, but should be interpreted literally.

For example: * is a special character that matches any character (including 0 characters);

For example:/a*/means matching 0 or more aces. To match the literal *, precede a with a backslash;

For example:/a*/matches ' A * '.

Character ^

Meaning: The character that represents the match must be at the front.

For example:/^a/does not match "an A," in the ' a ', but matches "an A." The "A" in the front.

Character $

Meaning: Similar to ^, matches the last character.

For example:/t$/does not match ' t ' in ' eater ', but matches ' t ' in ' eat '.

Characters

Meaning: matches the preceding character 0 or n times.
For example:/bo*/matches ' B ' in ' boooo ' or ' a bird warbled ' in ' a ghost booooed ', but does not match ' agoat G '
Any characters in the runted ". Character +
Meaning: Matches the character preceding the + sign 1 or n times. Equivalent to {1,}.

For example:/a+/matches ' a ' and ' Caaaaaaandy ' in ' Candy '. All ' a ' in the.

Character?

Meaning: match the preceding character 0 or 1 times.

For example:/e?le?/matches ' el ' and ' angle ' in ' Angel '. In the ' Le '.

Character.

Meaning: (decimal point) matches all the individual characters except the line break.

For example:/.n/matches "Nay, an apple was on the tree" in the ' an ' and ' on ', but does not match ' nay '.

Character (x)

Meaning: Match ' x ' and record the matching value.
For example:/(foo)/Match and record "Foo bar." In the ' foo '. The matched substring can be in the result array of the vegetarian [1], ..., [n] Return

Back, or the property of the RegExp object, ..., returns.

Character X│y

Meaning: Match ' x ' or ' Y '.

For example:/green│red/matches ' green ' and ' Red apple ' in ' green apple '. In the ' Red '.

Character {n}

Meaning: n Here is a positive integer. Matches the preceding n characters.

For example:/a{2}/does not match ' a ' in ' Candy, ' but matches all ' a ' and ' Caaandy ' in ' Caandy, '. In front of the two ' a '.

Character {n,}

Meaning: n Here is a positive integer. Matches at least n preceding characters.

For example:/a{2,} does not match ' a ' in ' Candy ', but matches all ' a ' and ' Caaaaaaandy ' in ' Caandy '. All ' a ' in the

Character {n,m}

Meaning: Both N and m are positive integers. Matches at least N of the characters up to M preceding.
For example:/a{1,3}/does not match any characters in "Cndy", but matches "candy," in the first two of ' a ', ' Caandy, '

' A ' and ' Caaaaaaandy ' in front of the three ' a ', note: even if "Caaaaaaandy" has a lot of ' a ', but only match the previous three ' a ' is "AAA".

character [XYZ]

Meaning: A list of characters that matches any one of the characters listed. You can use hyphens-to indicate a range of characters.

For example: [ABCD] is the same as [a-c]. They match ' C ' in ' B ' and ' ache ' in ' brisket '.

character [^XYZ]

Meaning: A character complement, that is, it matches everything except the listed characters. You can use hyphens-to indicate a range of characters.

For example: [^ABC] and [^a-c] are equivalent, they first match ' R ' and ' chop ' in ' brisket '. In the ' H '.

Character

Meaning: Match a space (do not confuse with B) Character B
Meaning: Match the dividing line of a word, such as a space (do not confuse)

For example:/bnw/matches ' no ' in ' Noonday ',/wyb/matches ' possibly yesterday. ' In the ' ly '.

Character B

Meaning: Match the non-dividing line of a word

For example:/wbn/matches ' on ' in "Noonday",/ybw/matches "possibly yesterday." In the ' ye '.

Character CX

Meaning: The x here is a control character. Matches the control character of a string.

For example:/cm/matches a control-m in a string.

Character D

Meaning: Match a number, equivalent to [0-9].

For example:/d/or/[0-9]/matches "B2 is the suite number." In the ' 2 '.

Character D

Meaning: matches any non-number, equivalent to [^0-9].

For example:/d/or/[^0-9]/matches "B2 is the suite number." In the ' B '.

Character F

Meaning: Match a form character n
Meaning: Match a line break character R
Meaning: Match a carriage return character s
Meaning: Match a single white space character, including spaces, tab,form feeds, line breaks, equivalent to [FNRTV].

For example:/sw*/matches "foo bar." In the ' bar '.

Character S

Meaning: matches a single character except white space, equivalent to [^ FNRTV].

For example:/s/w* matches "foo bar." In the ' foo '.

Character T

Meaning: Match a tab character V
Meaning: Match a head tab character W
Meaning: Matches all numbers and letters as well as underscores, equivalent to [a-za-z0-9_].

For example:/w/matches "Apple," in the ' a ', ". 28," In the ' 5 ' and ' 3D. ' In the ' 3 '.

Character W

Meaning: Matches other characters except numbers, letters, and underscores, equivalent to [^a-za-z0-9_].

For example:/w/or/[^ $A-za-z0-9_]/match "50%." In the '% '.

Character N

Meaning: n Here is a positive integer. Matches the value of N of the last substring of a regular expression (counting the left parenthesis).

For example:/apple (,) sorange1/matches "Apple, orange, cherry, peach." In the ' Apple, Orange ', here's a more complete example.

Note: If the number in the left parenthesis is smaller than the number specified by N, then N takes a line of octal escape as a description.

Characters Ooctal and Xhex

Meaning: The ooctal here is an octal escape value, while Xhex is a hexadecimal escape value that allows the embedding of ASCII code in a regular expression.

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