Matching numbers in String using Regex

Question

I'm attempting to parse the value of @id from inside an xPath expression like:

"/hrdg:data/hrdg:meeting[@code='30J7Q']/hrdg:event[@id='2545525']/hrdg:selection[@id='31192111']"

I have written this regular expression, and am using thefollowing code for matching:

 Pattern selectionIdPattern = Pattern.compile(".*/hrdg:selection[@id=\'(\\d+)\'].*");
 // Grab the xPath from the XML.
 xPathData = // Loaded from XML..;
 // Create a new matcher, using the id as the data.
 Matcher matcher = selectionIdPattern.matcher(xPathData);
 // Grab the first group (the id) that is loaded.
 if(matcher.find())
 {
     selectionId = matcher.group(1);
 }

However selectionId does not contain the value after @id=.

Example of Desired Outcome

For example, with the above statement, I want to get:

"/hrdg:data/hrdg:meeting[@code='30J7Q']/hrdg:event[@id='2545525']/hrdg:selection[@id='31192111']"

Data I want: 31192111

Bernhard Barker · Accepted Answer · 2013-09-03 11:00:06Z

2

You need to escape the [ and ], as these are also regex characters.

And if you're doing find (as opposed to matches), you may as well take out .* at the start and the end.

Regex:

"/hrdg:selection\\[@id='(\\d+)'\\]"

edited Sep 3, 2013 at 11:00

answered Sep 3, 2013 at 10:49

Bernhard Barker

55.7k14 gold badges111 silver badges143 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

zapl Over a year ago

Pattern.compile("/hrdg:event\\[@id='(\\d+)'\\]/") since you have to escape the \ to be valid in a String. ' needs no escaping.

Joe · Accepted Answer · 2013-09-03 11:04:58Z

2

String s = "/hrdg:data/hrdg:meeting[@code='30J7Q']/hrdg:event[@id='2545525']/hrdg:selection[@id='31192111']";
Pattern pattern = Pattern.compile("(?<=selection\\[@id=')\\w+(?='])");
Matcher matcher = pattern.matcher(s);
matcher.find();
System.out.println(matcher.group());

Output : 31192111

edited Sep 3, 2013 at 11:04

Joe

15.6k8 gold badges51 silver badges57 bronze badges

answered Sep 3, 2013 at 10:48

user2742695

Comments

David Sainty · Accepted Answer · 2013-09-03 10:48:03Z

1

The [] characters are indicating to match a character out of those in between. You'll need to escape the square brackets.

answered Sep 3, 2013 at 10:48

David Sainty

1,49813 silver badges10 bronze badges

Comments

Ruchira Gayan Ranaweera · Accepted Answer · 2013-09-03 10:48:04Z

1

If your all Strings like this, you can try this

 String str="/hrdg:data/hrdg:meeting[@code='30J7Q']/
    hrdg:event[@id='2545525']/hrdg:selection[@id='31192111']";
 int index=str.lastIndexOf("@id");
 System.out.println(str.substring(index+5,str.length()-2));

answered Sep 3, 2013 at 10:48

Ruchira Gayan Ranaweera

35.7k17 gold badges78 silver badges117 bronze badges

Comments

Reimeus · Accepted Answer · 2013-09-03 11:32:59Z

1

You need to escape the character class characters [ and ] in the regular expression used in Pattern selectionIdPattern

String xPathData = "/hrdg:data/hrdg:meeting[@code='30J7Q']/hrdg:event[@id='2545525']/hrdg:selection[@id='31192111']";
Pattern selectionIdPattern = Pattern.compile(".*/hrdg:selection\\[@id=\'(\\d+)\'\\]");
Matcher matcher = selectionIdPattern.matcher(xPathData);
if (matcher.find()) {
     String selectionId = matcher.group(1); // now matches 31192111
     ...
}

Since Matcher#find does partial matches, the wilcard characters .* can also be removed from the expression

Demo

edited Sep 3, 2013 at 11:32

answered Sep 3, 2013 at 10:46

Reimeus

160k16 gold badges225 silver badges282 bronze badges

Collectives™ on Stack Overflow

Matching numbers in String using Regex

5 Answers 5

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related