JS Regular Expression Replace substitution variable method _javascript tips

JavaScript is actual combat (will be updated according to the most recent write)

1. JavaScript regular object substitution creation and usage:/pattern/flags First simple case study know what replace can do

Regular expression constructor: New RegExp ("pattern" [, "flags"]);
Regular expression substitution variable function: stringobj.replace (regexp,replace Text);

Parameter description:

Pattern--a regular expression literal
Flags--if present, will be the following values:
G: Global Match
I: Ignore case
GI: Above combination

The following example is used to get the two parameters of the URL and return the real URL before urlrewrite the Var reg=new RegExp (http://www.qidian.com/BookReader/) (\\d+), (\\d+).
aspx "," GMI ");

var url= "http://www.qidian.com/BookReader/1017141,20361055.aspx";
Way one, the simplest common way of Var rep=url.replace (Reg, "$1showbook.aspx?bookid=$2&chapterid=$3");

Alert (rep); Mode two, a callback function with fixed parameters var rep2=url.replace (reg,function (M,P1,P2,P3) {return p1+ "showbook.aspx?bookid=" &
Chapterid= "+p3}";

alert (REP2); Mode three, the callback function with the unfixed parameter var rep3=url.replace (Reg,function () {var args=arguments; return args[1]+ "showbook.aspx?bookid=" +
args[2]+ "&chapterid=" +args[3];


alert (REP3);
Method four//mode four and method three very similar, in addition to returning the replacement string, you can also get the parameter Var BookID;
var Chapterid; 
  function Captext () {var args=arguments;
  BOOKID=ARGS[2];
  CHAPTERID=ARGS[3];
return args[1]+ "showbook.aspx?bookid=" +args[2]+ "&chapterid=" +args[3];
} var rep4=url.replace (reg,captext);
alert (REP4);
alert (BookID);


alert (Chapterid); Use the test method to get the group Var reg3=new RegExp (http://www.qidian.com/BookReader/) (\\d+), (\\d+). ASPX "," GMI ");
Reg3.test ("http://www.qidian.com/BookReader/1017141,20361055.aspx"); 
Gets three group alert (regexp.$1);
alert (regexp.$2); alert (regexp.$3);

2, learn the most commonly used test exec match search replace split 6 methods

1 Test checks to see if the specified string exists
var data = "123123″;"
var recat =/123/gi;
Alert (recat.test (data)); True
Check to see if the character is present G continue to go down I case insensitive

2 Exec return query value
var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/i;
Alert (recat.exec (data)); Cat

3 Match Gets the query array
var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/gi;
var arrmactches = Data.match (recat)
for (Var i=0;i < arrmactches.length; i++)
{
Alert (Arrmactches[i]); Cat Cat
}

4 Search to return to a location similar to IndexOf
var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/gi;
Alert (Data.search (Recat)); 23

5 Replace replacement character using regular substitution
var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/gi;
Alert (Data.replace (Recat, "libinqq"));

6) split using a regular split array
var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/\,/;
var arrdata = Data.split (recat);
for (var i = 0; i < arrdata.length; i++)
{
Alert (Arrdata[i]);
}
3. Common Expression Collection:

"^\\d+$"//non-negative Integer (positive integer + 0)
"^[0-9]*[1-9][0-9]*$"//Positive integer
"^ ((-\\d+) | (0+)) $ "//non-positive integer (negative integer + 0)
"^-[0-9]*[1-9][0-9]*$"//Negative integer
"^-?\\d+$"//Integer
"^\\d+ (\\.\\d+)? $"//nonnegative floating-point number (positive float + 0)
"^ ([0-9]+\\. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*)] $"
Positive floating-point numbers
"^ ((-\\d+ (\\.\\d+)?) | (0+ (\\.0+)) $ "//non-positive floating-point number (negative floating-point number + 0)
^ (-([0-9]+\\. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*))] $"
Negative floating-point numbers
"^ (-?\\d+) (\\.\\d+)? $"//floating-point number
"^[a-za-z]+$"//A string of 26 English letters
"^[a-z]+$"//A string of 26 uppercase letters
"^[a-z]+$"///a string consisting of 26 lowercase letters
"^[a-za-z0-9]+$"//A string of numbers and 26 English letters
"^\\w+$"//A string of numbers, 26 English letters, or underscores
"^[\\w-]+ (\\.[ \\w-]+) *@[\\w-]+ (\\.[ \\w-]+) +$ "//email address
"^[a-za-z]+://(\\w+ (-\\w+) *) (\ \\w+ (-\\w+) *)) * (\\?\\s*) $ "//url
"^[a-za-z0-9_]*$".

Basic knowledge of regular expressions

The

^ matches the beginning of an input or line./^a/matches "an A", but does not match "an A"
$ matches an input or a line end,/a$/matches "an A", but does not match "an A"
* matches the preceding metacharacters 0 or more times,/ba*/will match B,ba,ba A,BAAA
+ matches the preceding metacharacters 1 or more times,/ba+/matches ba,baa,baaa
? Matches the preceding metacharacters 0 or 1 times,/ba?/matches the B,ba
(x) match X to save x in the variable named $1...$9
x|y match x or y
{n} exact match n times
{n,} matches n above
{n,m} matching n-m times
[XYZ] Character set (character set), matching any one by one characters (or metacharacters) in this collection
[^xyz] does not match this Any one of the characters in the collection
[\b] matches a backspace
\b The bounds of a word
\b match the non-boundary of a word
\cx here, X is a control character,/\cm/match ctrl-m
\d match a character number character,/\d/ =/[0-9]/
\d matches a non-numeric character,/\d/=/[^0-9]/
\ n matches a newline character
\ r matches a carriage return
\s matches a white space character, including \n,\r,\f,\t,\v, etc.
\s match one A non-white-space character equal to/[^\n\f\r\t\v]/
\ t matches a tab
\v matches a single tab
\w matches a character that can make up a word (alphanumeric, this is my transliteration, with numbers), including underscores, such as [\w] matching 5 in "$5.98" equals [a-za-z0-9]
\w matches a character that cannot be made into words, such as [\w] matches $ in "$5.98", equal to [^a-za-z0-9].