asked on

Java regex needed

Hi,

How can I use the attached code to extract "B004UJLUQU" from "dp/B004UJLUQU"?

The attached code returns the first matched string, and has been very helpful in the past such that I don't want to change it.

Thanks

public static String extractRegex(String source, String regex){
		Pattern re = Pattern.compile(regex, Pattern.DOTALL|Pattern.MULTILINE|Pattern.CASE_INSENSITIVE);
		Matcher m = re.matcher(source);
		while (m.find())
			return m.group(0);
		return null;
	}

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CEHJ

Something like the following should work

public static String extract(String s) {
        return s.replaceAll(".*?/(.*)", "$1");
    }

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for_yan

Why wouldnot you use "B004UJLUQU" as the pattern:

public static String extractRegex(String source, String regex){
		Pattern re = Pattern.compile("B004UJLUQU", Pattern.DOTALL|Pattern.MULTILINE|Pattern.CASE_INSENSITIVE);
		Matcher m = re.matcher(source);
		while (m.find())
			return m.group(0);
		return null;
	}

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for_yan

I tested this:

                 String source = "dp/B004UJLUQU";

//public static String extractRegex(String source, String regex){
		Pattern re = Pattern.compile("/(.+)$", Pattern.DOTALL|Pattern.MULTILINE|Pattern.CASE_INSENSITIVE);
		Matcher m = re.matcher(source);
		while (m.find())
			System.out.println(m.group(1));
	//	return null;

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Output:

B004UJLUQU

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for_yan

This is as a method, though I changed group(0) to group(1):

  public static String extractRegex(String source, String regex){
		Pattern re = Pattern.compile(regex, Pattern.DOTALL|Pattern.MULTILINE|Pattern.CASE_INSENSITIVE);
		Matcher m = re.matcher(source);
		while (m.find())
			return m.group(1);
		return null;
	}


		   public static void main(String[] args){





                 String source = "dp/B004UJLUQU";
                  String regex = "/(.+)$";
           System.out.println(extractRegex( source, regex));

}

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Output:

B004UJLUQU

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for_yan

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wsyy

ASKER

CEH, I don't want to change group(0) in the method.

for_yan, the last method you provided works. can you please explain it a little bit?

I guess that (?<=/) removes the "/", but I don't understand the ".+$" part.

for_yan

.+ this maens any charcter any tnumber of times but at least once
$ - means the end of the string

for_yan

So it looks for the slash and then picks up anything after the slash to th end of the string

for_yan

and this is called positive lookbehind (?<=/) - it checks that ther is a slash before , but does not include it into match

wsyy

ASKER

Many thanks!