Regular Expression rule syntax

Regular Expression rule syntax

What is the role of a regular expression?

It can:

? Test a mode of a string. For example, you can test an input string to see if there is a phone number or a credit card number. This is called Data Validity verification;
? Replace text. You can use a regular expression in a document to identify a specific text, and then delete it all or replace it with another text;

? Extract a substring from the string based on the pattern match. It can be used to search for specific text in text or input fields;

The next article provides examples to illustrate how to use the following rules.

Modifier

Modifier	Description
I	Perform case-insensitive matching.
G	Perform global match (search for all matches instead of stopping the first match ).
M	Perform multi-row matching.

Square brackets

Square brackets are used to find characters in a certain range:

Expression	Description
[Abc]	Find any character between square brackets.
[^ Abc]	Search for any characters that are not in square brackets.
[0-9]	Search for any number ranging from 0 to 9.
[A-z]	Search for any characters from lowercase to lowercase.
A-Z	Search for any characters from uppercase A to uppercase Z.
[A-z]	Search for any characters from uppercase A to lowercase z.
[Adgk]	Searches for any character in a given set.
[^ Adgk]	Searches for any characters outside the given set.
(Red | blue | green)	Find any specified options.

Metacharacters

Metacharacter is a character with special meanings:

Metacharacters	Description
.	Searches for a single character, except for line breaks and line Terminators.
\ W	Search for word characters.
\ W	Searches for non-word characters.
\ D	Search for numbers.
\ D	Searches for non-numeric characters.
\ S	Search for blank characters.
\ S	Searches for non-blank characters.
\ B	Match the word boundary.
\ B	Match non-word boundary.
\ 0	Search for NUL characters.
\ N	Find a line break.
\ F	Find a break.
\ R	Find the carriage return.
\ T	Search for tabs.
\ V	Search for vertical tabs.
\ Xxx	Search for characters specified by octal xxx.
\ Xdd	Search for the characters specified by dd in hexadecimal notation.
\ Uxxxx	Find the Unicode characters specified by the hexadecimal number xxxx.

Quantifiers

Quantifiers	Description
N +	Match any string containing at least one n.
N *	Match any string containing zero or more n.
N?	Match any string containing zero or one n.
N {X}	Matches the string that contains X n sequences.
N {X, Y}	Matches the string that contains X or Y n.
N {X ,}	Matches strings that contain at least X n sequences.
N $	Match any string ending with n.
^ N	Match any string starting with n.
? = N	Match any string followed by the specified string n.
?! N	Match any string that is not followed by the specified string n.

RegExp Object Attributes

Attribute	Description	FF	IE
Global	Whether the RegExp object has a flag.	1	4
IgnoreCase	Whether the RegExp object has a flag I.	1	4
LastIndex	An integer that indicates the position of the next matched character.	1	4
Multiline	Whether the RegExp object has a flag m.	1	4
Source	The Source Text of the regular expression.	1	4

RegExp object Method

Method	Description	FF	IE
Compile	Compile a regular expression.	1	4
Exec	Returns the value specified in the string. Return the value found and locate it.	1	4
Test	Returns the value specified in the string. Returns true or false.	1	4

Methods for String objects that support regular expressions

Method	Description	FF	IE
Search	Returns the value that matches the regular expression.	1	4
Match	Find the matching of one or more regular expressions.	1	4
Replace	Replace the substring that matches the regular expression.	1	4
Split	Splits a string into a string array.	1	4