[Js source code] Quick Start Regular Expression

I haven't looked at regular expressions for a long time. It happened to be used today. I learned how to read a book and learn about the originality in 50% exercises.

I haven't read the regular expression for a long time. I happen to use it today. I just learned how to read a book.
In 50%, the original practices are described in the opposite way.

I. Basic knowledge about javascript Regular Expressions

1. Create and use a javascript Regular object

Declare a javascript Regular Expression

VarreCat = newRegExp ("cat ");

You can also

VarreCat =/cat/; // Perl style (recommended)

2. Learn the most common test exec match search replace split six methods.

1) test checks whether the specified string exists

Vardata = "123123"; varreCat =/123/gi; alert (reCat. test (data); // true

// Check whether the character g exists. continue to the next step. I is case insensitive.

2) exec returns the query value

Vardata = "123123,213,123, 3, Cat, cat, dsfsdfs,"; varreCat =/cat/imo-alert(recat.exe c (data); // Cat

3) match to get the query Array

Vardata = "123123,213,123, 312, 3, Cat, cat, dsfsdfs,"; varreCat =/cat/gi; vararrMactches = data. match (reCat) for (vari = 0; I <arrMactches. length; I ++) {alert (arrMactches [I]); // Cat cat}

4) The returned search location is similar to indexof.

Vardata = "123123,213,123, 3, Cat, cat, dsfsdfs,"; varreCat =/cat/gi; alert (data. search (reCat); // 23

5) replace replacement characters with regular expressions

Vardata = "123123,213,123, 3, Cat, cat, dsfsdfs,"; varreCat =/cat/gi; alert (data. replace (reCat, "libinqq "));

6) split splits the array using regular expressions.

Vardata = "123123,213,123, 312, 3, Cat, cat, dsfsdfs,"; varreCat = //,/; vararrdata = data. split (reCat); for (vari = 0; I <arrdata. length; I ++) {alert (arrdata [I]);}

3. Learning simple class negative class range class combination class

// Simple class vardata = "1 libinqq, 2 libinqq, 3 libinqq, 4 libinqq"; varreCat =/[123] libinqq/gi; vararrdata = data. match (reCat); for (vari = 0; I <arrdata. length; I ++) {alert (arrdata [I]); // 1 libinqq 2 libinqq 3 libinqq} // negative class vardata = "alibinqq, 1 libinqq, 2 libinqq, 3 libinqq, 4 libinqq "; // \ u0062cfvarreCat =/[^ a123] libinqq/gi; vararrdata = data. match (reCat); for (vari = 0; I <arrdata. length; I ++) {alert (arrdata [I]); // 4 libinqq} // range class vardata = "libinqq1, libinqq2, libinqq3, libinqq4, libinqq5 "; // \ u0062cfvarreCat =/libinqq [2-3]/gi; vararrdata = data. match (reCat); for (vari = 0; I <arrdata. length; I ++) {alert (arrdata [I]); // libinqq2 libinqq3} // vardata = "a, B, c, w, 1, 2, 3, 5 "; // \ u0062cfvarreCat =/[a-q1-4 \ n]/gi; vararrdata = data. match (reCat); for (vari = 0; I <arrdata. length; I ++) {alert (arrdata [I]); // a B c 1 2 3}