Note 007: Object--regexp Regular Expression object

1, REGEXP

• A pattern text for matching
• Matching pattern details described with 0 or more modifiers

form of RegExp object creation

• Create var re = new RegExp ("J.*t") with the built-in constructor
• The text is defined in the way var re =/j.*t/;

2. RegExp Object Properties

• G==>global: Whether the related search stops when the first match is found (false default)
• I==>ignorecase: Ignore case (false default)
• M==>multiline: Sets the option to search across rows, default to False
• LastIndex: Index location for search start, default to 0
• Source: The property used to store the regular expression matching pattern
• Except for lastindex, objects cannot be modified after they are created.

var re = new RegExp (' j.*t ', ' gmi ');

var re =/j.*t/ig;

2. Methods of RegExp objects

• Test () returns a Boolean value that is true when matching content is found
• EXEC () returns an array consisting of matching strings

/j.*t/.test ("Javascript") ==>false

/j.*t/i.test ("JavaScript") ==> true

/j.*t/i.exec ("Javscript") [0] ==> "Javascript"

• Match (): Returns an array containing the matching contents
• Search (): Returns where the first match is located
• Replace (): Replaces the matched text with the specified string
• Split (): Splits the target string into a number of array elements

var s = new String ("Hellojavascriptworld");

S.match (/a/); ==>["a"]

S.match (/a/g) ==>["A", "a"]

S.replace (/[a-z]/g, ') ==> "Elloavacriptorld"

Use $& to represent matching text when matching objects are found

S.replace (/[a-z]/g, ' _$&') ==> "_hello_java_script_world"//Match text before adding _

If the regular expression is divided into groups (with parentheses), the first group that matches the grouping is used, and so on

S.replace (/([A-z])/g,' _ $ ') ==> "_hello_java_script_world"//Match text before adding _

Note 007: Object--regexp Regular Expression object