Detailed explanation of the method of obtaining group content using JS regular expression_javascript skills

Support multiple matching methods:

Copy code The code is as follows:

var testStr = "now test001 test002";
var re = /test(d )/ig;
var r = "";
while(r = re.exec(testStr)) {
alert(r[0] " " r[1] );
}

You can also use testStr.match(re), but in this case you cannot have the g option, and you can only get the first match.

Another note:

Properties and methods of regular expression objects:
Predefined regular expressions have the following static properties: input, multiline, lastMatch, lastParen, leftContext,

rightContext and $1 to $9. Among them, input and multiline can be preset. The values ​​of other attributes are determined according to

after executing the exec or test method.

Different conditions are assigned different values. Many properties have both long and short (perl-style) names, and both names refer to the same value. (JavaScript simulates perl’s regular expression)

Attributes of the regular expression object:
Attribute meaning
$1...$9 If they (they) exist, it is the matched substring
$_ See input
$* See multiline
$& See lastMatch
$ See lastParen
$` See leftContext
$''　 See rightContext
constructor Create a special function prototype of an object
global Whether it is in the entire string Match (bool type)
ignoreCase Whether to ignore case when matching (bool type)
input The matched string
lastIndex The last matched index
lastParen The last substring enclosed in parentheses
leftContext　 The most recent matched substring to the left
multiline　　 Whether to perform multi-line matching (bool type)
prototype　　 Allow additional attributes to the object
rightContext　　 The most recent matched substring to the right
source　　 Regular expression Formula pattern
lastIndex　 The index of the last match

Methods of regular expression objects:
Method meaning
compile　　This should refer to redefining the content of the regular expression
exec　　To perform a search, you can use the while method to search multiple times for
test　　　Matches
toSource Returns the literal representation of a specific object, whose value can be used to create a new object. Obtained by overloading the Object.toSource method.
toString　　　 Returns the string of a specific object. Obtained by overloading the Object.toString method.
valueOf　　　 Returns the original value of a specific object. Overload the Object.valueOf method to get

Example:

Copy the code The code is as follows:

will output "Smith, John"