Regular Expressions methods and usage
Now, knowing how a RegExp is written is only half the game. To gain anything from them you have to know how to use them too. There are a number of ways to implement a RegExp, some through methods belonging to the String object, some through methods belonging to the RegExp object. Whether the regular expression is declared through an object constructor or a literal makes no difference as to the usage.
| Description | Example |
|---|---|
RegExp.exec(string) |
|
| Applies the RegExp to the given string, and returns the match information. | var match = /s(amp)le/i.exec("Sample text")match then contains ["Sample","amp"] |
RegExp.test(string) |
|
| Tests if the given string matches the Regexp, and returns true if matching, false if not. | var match = /sample/.test("Sample text")match then contains false |
String.match(pattern) |
|
Matches given string with the RegExp. With g
flag returns an array containing the matches, without g
flag returns just the first match or if no match is found returns
null. |
var str = "Watch out for the rock!".match(/r?or?/g)str then contains ["o","or","ro"] |
String.search(pattern) |
|
| Matches RegExp with string and returns the index of the beginning of the match if found, -1 if not. | var ndx = "Watch out for the rock!".search(/for/)ndx then contains 10 |
String.replace(pattern,string) |
|
| Replaces matches with the given string, and returns the edited string. | var str = "Liorean said: My name is
Liorean!".replace(/Liorean/g,'Big Fat Dork')str then contains "Big Fat Dork said: My name
is Big Fat Dork!" |
String.split(pattern) |
|
| Cuts a string into an array, making cuts at matches. | var str = "I am confused".split(/\s/g)str then contains ["I","am","confused"] |
On that note I conclude the tutorial. Now go express yourself with JavaScript regular expressions!
- Tutorial introduction
- Regular Expression patterns
- Regular Expression methods and usage
This tutorial is written by David Andersson (Liorean). Liorean is a twenty years old medical student and hobbyist web designer mostly working with JavaScript and CSS, DOM and the newest html standards available.
