JS - Regular Expressions

This article introduces the content of js regular expressions. Now I share it with you and give you a reference. Let’s take a look together now

##+ matches the preceding metacharacter 1 or more times, /ba*/ will match ba, baa, baaaLow? matches the preceding metacharacter 0 or 1 times, /ba*/ will match b,balow (x) Matches x and saves x in a variable named Lowx|yMatch x or y中{n}Exactly match n times{n,}Match more than n times中{n,m}match n-m times 中##[ xyz][ ^xyz]##[\b]matches a return The case character 中 matches the boundary of a word Match a non-boundary word Here, X is a control character, /\cM/ matches Ctrl-M matches an alphanumeric character, /\d/ = /[0-9] / matches a non-alphanumeric character, /\D/ = /[^0-9]/ Matches a newline character Matches a carriage return character Matches a blank character, including \n, \r, \f ,\t,\v, etc. matches a non-whitespace character, equal to /[^\n\f\r \t\v]/matches a tab charactermatches a double tab matches A character that can form a word (alphanumeric, this is my free translation, including numbers), including underscores, such as [\w] matching 5 in "$5.98", which is equal to [a-zA-Z0-9]##\W matches a character that cannot form a word, such as [\W] matching "

Create a regular description object:
var pattern = /\w/;
or
var pattern = new RegExp( /\w/)

Test whether the string is regular:
pattern.test(0)
Note: The previously created regular pattern matches the text between 0-9a-zA-Z , if they all match, return true

17 commonly used regular expressions:

Symbol	Meaning	Common usage
\	Changing meaning , that is, usually the characters after "\" are not interpreted according to their original meaning. For example, /b/ matches the character "b". When a backslash is added in front of b, /\b/ changes the meaning to match the boundary of a word.	高
-	Reduction of regular expression function characters, such as "" matches the metacharacter before it 0 or more times times, /a/ will match a, aa, aaa. After adding "\", /a*/ will only match "a*".	高
^	Matches an input or the beginning of a line, /^a/ matches "an A", but does not match "An a "	高
$	matches an input or the end of a line, /a$/ matches "An a", but does not match "an A”	高
*	matches the preceding metacharacter 0 or more times, /ba*/ will match b,ba,baa, baaa	高
	9
Character set (character set), matches any character (or metacharacter) in this set	高
Does not match any character in this set	High
		##\b
中		\B
中		\cX
		\d
高		\D
High		\n
中		\r
in		\s
	\S	in
中		\t
中		\v
中		\w
高
	, equal to [^a-zA-Z0-9]高

##ExpressionUse//Non-negative integer (positive integer + 0) //Positive integer//Non-positive integer (negative integer + 0) //Negative integer//Integer##^\\d+(\\.\\d+)?$^(([0-9]+\\.[0- 9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]*\\.[0-9]+)|([0-9 ]*[1-9][0-9]*))$^((-\ \d+(\\.\\d+)?)|(0+(\\.0+)?))$^(-(([0-9]+\\.[0-9]*[1-9][0-9]*)|([0 -9]*[1-9][0-9]*\\.[0-9]+)|([0-9]*[1-9][0-9]*)))$^(-?\\d+)(\\.\\d+)?$##^[A-Za-z]+$^[A-Z]+$^[a-z]+$^[A-Za-z0-9]+$^\\w+$##^[\ \w-]+(\\.[\\w-]+)*@[\\w-]+(\\.[\\w-]+)+$^[a-zA-z]+://(\\w+(-\\w+)*)(\\.(\\w+ (-\\w+)*))*(\\?\\S*)?$

^\\d+$

^[0-9]*[1-9][0-9]*$

^((-\\d+)|(0+))$

^-[0-9]*[1-9][0-9]*$

^-?\\d+$

//Non-negative floating point number (positive floating point number + 0)

//Positive floating point number

//Non-positive floating point number (negative floating point number + 0)

//Negative floating point number

//Floating point number

//Composed of 26 English letters The string

//A string consisting of 26 uppercase English letters

//A string consisting of 26 lowercase English letters

//A string consisting of numbers and 26 English letters

//A string consisting of numbers, 26 English letters or underscores

/ /email address

//url

##+ matches the preceding metacharacter 1 or more times, /ba*/ will match ba, baa, baaaLow? matches the preceding metacharacter 0 or 1 times, /ba*/ will match b,balow (x) Matches x and saves x in a variable named Lowx|yMatch x or y中{n}Exactly match n times{n,}Match more than n times中{n,m}match n-m times 中##[ xyz][ ^xyz]##[\b]matches a return The case character 中 matches the boundary of a word Match a non-boundary word Here, X is a control character, /\cM/ matches Ctrl-M matches an alphanumeric character, /\d/ = /[0-9] / matches a non-alphanumeric character, /\D/ = /[^0-9]/ Matches a newline character Matches a carriage return character Matches a blank character, including \n, \r, \f ,\t,\v, etc. matches a non-whitespace character, equal to /[^\n\f\r \t\v]/matches a tab charactermatches a double tab matches A character that can form a word (alphanumeric, this is my free translation, including numbers), including underscores, such as [\w] matching 5 in "$5.98", which is equal to [a-zA-Z0-9]##\W matches a character that cannot form a word, such as [\W] matching "

Create a regular description object:
var pattern = /\w/;
or
var pattern = new RegExp(/\w/)

Test whether the string is regular:
pattern.test(0)
Note: The previously created regular pattern matches the text between 0-9a-zA-Z, and returns true if they all match

17 commonly used regular expressions:

Symbol	Meaning	Common usage
\	Change the meaning, that is, usually the characters after "\" are not interpreted according to the original meaning. For example, /b/ matches the character "b". When a backslash is added in front of b, /\b/, the meaning is changed to match a word boundaries.	高
-	Reduction of regular expression function characters, such as "" matches the metacharacter before it 0 or more times times, /a/ will match a, aa, aaa. After adding "\", /a*/ will only match "a*".	高
^	Matches an input or the beginning of a line, /^a/ matches "an A", but does not match "An a "	高
$	matches an input or the end of a line, /a$/ matches "An a", but does not match "an A”	高
*	matches the preceding metacharacter 0 or more times, /ba*/ will match b,ba,baa, baaa	高
	9
Character set (character set), matches any character (or metacharacter) in this set	高
Does not match any character in this set	High
		##\b
中		\B
中		\cX
		\d
高		\D
High		\n
中		\r
in		\s
	\S	in
中		\t
中		\v
中		\w
高
	, equal to [^a-zA-Z0-9]高

//Non-negative integer (positive integer + 0) //Positive integer//Non-positive integer (negative integer + 0) ##^-[0 -9]*[1-9][0-9]*$^-?\\d+ $##^\\d+(\\.\\d+)?$^(([0-9]+\\.[0-9]*[1- 9][0-9]*)|([0-9]*[1-9][0-9]*\\.[0-9]+)|([0-9]*[1-9 ][0-9]*))$^((-\\d+(\\. \\d+)?)|(0+(\\.0+)?))$^(-(([0-9]+\\.[0-9]*[1-9][0-9]*)|([0-9]*[1 -9][0-9]*\\.[0-9]+)|([0-9]*[1-9][0-9]*)))$^(-?\\d+)(\\.\\d+)?$^[A-Za-z]+$^[A-Z]+$^[a-z]+$^[ A-Za-z0-9]+$##^\\ w+$^[\\w-]+( \\.[\\w-]+)*@[\\w-]+(\\.[\\w-]+)+$^[a-zA-z]+://(\\w+(-\\w+)*)(\\.(\\w+(-\\w+) *))*(\\?\\S*)?$##Related recommendations: JS regular expressions detailed explanation

Expression	Use
##^\\d+$
^ [0-9]*[1-9][0-9]*$
^((- \\d+)|(0+))$
//Negative integer
//Integer
//Non-negative floating point number (positive floating point number + 0)
//Positive floating point number
//Non-positive floating point number (negative floating point number + 0)
//Negative floating point number
// Floating point number
//String consisting of 26 English letters
//A string consisting of 26 uppercase English letters
//A string consisting of 26 lowercase English letters
//A string consisting of numbers and 26 English letters
//A string consisting of numbers, 26 English letters or underscores
//email address
//url

The use and basic syntax of JS regular expressions

Summary of the key points of JS regular expressions

The above is the detailed content of JS - Regular Expressions. For more information, please follow other related articles on the PHP Chinese website!