Problem with Actionscript Regular Expressions - regex

Question

I have to parse out color information from HTML data. The colors can either be RGB colors or file names to a swatch image.
I used http://www.gskinner.com/RegExr/ to develop and test the patterns. I copied the AS regular expression code verbatim from the tool into Flex Builder. But, when I exec the pattern against the string I get a null.
Here are the patterns and an example of the string (I took the correct HTML tags out so the strings would show correctly):
DIV data:
<div style="background-color:rgb(2,2,2);width:10px;height:10px;">
DIV pattern:
/([0-9]{1,3},[0-9]{1,3},[0-9]{1,3})/
IMG data:
<img src="/media/swatches/jerzeesbirch.gif" width="10" height="10" alt="Birch">
IMG pattern:
/[a-z0-9_-]+/[a-z0-9_-]+/[a-z0-9_-]+\.[a-z0-9_-]+/
Here's my Actionscript code:
var divPattern : RegExp = new RegExp("/([0-9]{1,3},[0-9]{1,3},[0-9]{1,3})/");
var imgPattern : RegExp = new RegExp("/[a-z0-9_-]+/[a-z0-9_-]+/[a-z0-9_-]+\.[a-z0-9_-]+/");
var divResult : Array = divPattern.exec(object.swatch);
var imgResult : Array = imgPattern.exec(object.swatch);
Both of the arrays are null.
This is my first foray into AS coding, so I think I'm declaring something wrong.
Steve

Answer 1

(I don't know ActionScript but I know Javascript and they should be close enough to solve your problem.)
To construct a RegExp object for e.g. the pattern ^[a-z]+$, you either use
var pattern : RegExp = new RegExp("^[a-z]+$");
or, better,
var pattern : RegExp = /^[a-z]+$/
The code new RegExp("/^[a-z]+$/") is wrong because this expects a slash before the ^ and after the $.
Therefore, your DIV pattern should be written as
var divPattern : RegExp = /([0-9]{1,3},[0-9]{1,3},[0-9]{1,3})/;
but, as you know, the ( and ) are special characters for capturing, you need to escape them:
var divPattern : RegExp = /\([0-9]{1,3},[0-9]{1,3},[0-9]{1,3}\)/;
For the IMG pattern, as / delimitates a RegEx, you need to escape it as well:
var imgPattern : RegExp = /[a-z0-9_-]+\/[a-z0-9_-]+\/[a-z0-9_-]+\.[a-z0-9_-]+/
Finally, you could use \d in place of [0-9] and \w in place of [a-zA-Z0-9_].

Answer 2

I don't know enough to tell if your regex patterns are correct, but from the docs on the AS3 RegExp class, it looks like your new RegExp() call needs a second argument to declare flags for case sensitivity etc.
EDIT: Also, as Bart K has pointed out, you don't need the / delimiters when using the new method.
So you can use either:
var divPattern:RegExp = new RegExp("([0-9]{1,3},[0-9]{1,3},[0-9]{1,3})", "");
OR you can also use the alternate syntax with /:
var divPattern:RegExp = /([0-9]{1,3},[0-9]{1,3},[0-9]{1,3})/;
... in which case the flag string (if any) is included after the final /