Character class of regular series

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Character classes can distinguish between various characters , For example, distinguish between letters and numbers .

1、.

Has one of the following meanings ：

1. Matches any single character except the line terminator ：\n（ A newline ）,\r（ A carriage return ）,\u2028（ Line separator ） perhaps \u2029（ Paragraph separator ）.

let reg = /.y/g;
let str = "yes make my day";
str.match(reg); // ['my', 'ay']

2. In the character set , Point loses its special significance , And match with the text points .

let reg = /\./g;
let str = ".u";
str.match(reg); // ['.']

Be careful ,m Multiline flags do not change the behavior of points . therefore , To match multiline patterns , You can use character classes [^], It will match any character including the newline character .

let reg = /[^]/g;
let str = ".u\n\r\u2028\u2029";
str.match(reg); // ['.', 'u', '\n', '\r', '
', '
']

ES2018 Added s“dotAll” sign , It allows the dot to also match the line terminator .

let reg = /./g;
let str = "yes make my day\n";
str.match(reg); // ['y', 'e', 's', ' ', 'm', 'a', 'k', 'e', ' ', 'm', 'y', ' ', 'd', 'a', 'y']
reg = /./gs;
str.match(reg); // ['y', 'e', 's', ' ', 'm', 'a', 'k', 'e', ' ', 'm', 'y', ' ', 'd', 'a', 'y', '\n']

2、\d

Match any number （ Arabic numerals ）. amount to [0-9].

let reg = /\d/g;
let str = "B2is the suite number";
str.match(reg); // ['2']

3、\D

Match any non number （ Arabic numerals ） The characters of . amount to [^0-9].

let reg = /\D/g;
let str = "B2is the suite number";
str.match(reg); // ['B', 'i', 's', ' ', 't', 'h', 'e', ' ', 's', 'u', 'i', 't', 'e', ' ', 'n', 'u', 'm', 'b', 'e', 'r']

4、\w

Matches any alphanumeric character in the Basic Latin alphabet , Include underline . amount to [A-Za-z0-9_].

let reg = /\w/g;
let str = "B2is_the-suite number";
str.match(reg); // ['B', '2', 'i', 's', '_', 't', 'h', 'e', 's', 'u', 'i', 't', 'e', 'n', 'u', 'm', 'b', 'e', 'r']

5、\W

Match any word character that is not from the Basic Latin alphabet . amount to [^A-Za-z0-9_].

let reg = /\W/g;
let str = "B2is_the-suite number";
str.match(reg); // ['-', ' ']

6、\s

Match a single white space character , Including Spaces 、 tabs 、 Page identifier 、 Line breaks and other Unicode Space . amount to [ \f\n\r\t\v\u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff].

let reg = /\s/g;
let str = "B2is_the-suite number\f\n\r\t\v\u00a0\u1680\u2000\u200a\u2028\u2029\u202f\u205f\u3000\ufeff";
str.match(reg);// [' ', '\f', '\n', '\r', '\t', '\v', ' ', ' ', ' ', ' ', '
', '
', ' ', ' ', '　', '']

7、\S

Match single characters other than spaces . amount to [^ \f\n\r\t\v\u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff].

reg = /\S/g;
str.match(reg); // ['B', '2', 'i', 's', '_', 't', 'h', 'e', '-', 's', 'u', 'i', 't', 'e', 'n', 'u', 'm', 'b', 'e', 'r']

8、\t

Match horizontal tabs .

let reg = /\t/g;
let str = "B2is_the-suite number\f\n\r\t\v\u00a0\u1680\u2000\u200a\u2028\u2029\u202f\u205f\u3000\ufeff";
str.match(reg); // ['\t']

9、\r

Match carriage return .

let reg = /\r/g;
let str = "B2is_the-suite number\f\n\r\t\v\u00a0\u1680\u2000\u200a\u2028\u2029\u202f\u205f\u3000\ufeff";
str.match(reg); // ['\r']

10、\n

Match newline .

let reg = /\n/g;
let str = "B2is_the-suite number\f\n\r\t\v\u00a0\u1680\u2000\u200a\u2028\u2029\u202f\u205f\u3000\ufeff";
str.match(reg); // ['\n']

11、\v

Match vertical tabs .

let reg = /\v/g;
let str = "B2is_the-suite number\f\n\r\t\v\u00a0\u1680\u2000\u200a\u2028\u2029\u202f\u205f\u3000\ufeff";
str.match(reg); // ['\v']

12、\f

Match page breaks .

let reg = /\f/g;
let str = "B2is_the-suite number\f\n\r\t\v\u00a0\u1680\u2000\u200a\u2028\u2029\u202f\u205f\u3000\ufeff";
str.match(reg); // ['\f']

13、[\b]

Match backspace key .

14、\0

Match one NUL character . Don't add another number after this .

15、\cX

Use caret to match control characters , among “X” yes A–Z One of the letters in （ Corresponding to code point U+0001–U+001F）.

let reg = /\cM/g;
let str = "\r\t";
str.match(reg); // ['\r']

16、\xhh

Match with code hh（ Two hexadecimal numbers ） Corresponding characters .

17、\uhhhh

Match with value hhhh（ Four hexadecimal numbers ） Corresponding UTF-16 Code unit .

18、\u{hhhh} or \u{hhhhh}

（ Only if u When marking .） Match with Unicode value U+hhhh or U+hhhhh（ Hexadecimal number ） Corresponding characters .

19、\p{UnicodeProperty},\P{UnicodeProperty}

According to the character Unicode Character attributes match characters （ for example , Only match emoticon characters 、 Japanese katakana characters 、 Chinese kanji characters or Japanese Kanji characters, etc ）.

20、\

Indicates that special treatment or “ escape ” Following character . It appears in one of two ways .

• For characters that are usually treated literally , Indicates that the next character is special , It cannot be explained literally . for example ,/b/ Matching character “b”. By means of “b” Put a backslash in front , That is to use /\b/, Characters become special to represent matching word boundaries .
• Usually treated as special characters , Indicates that the next character is not special , It should be interpreted literally . for example ,“*” It's a special character , Indicates that it should match the previous characters 0 Times or times ; for example ,/a*/ Show matching 0 One or more “a”. To match literally * It needs to be preceded by a backslash ; for example ,/a\*/ matching “a*”.

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