String pattern matching with regular expression in java

Question

I'm trying pattern matching expression for a below string. But it doesn't work. could you anybody help me on this ? Only Alphanumeric and underscore allowed inside,Both side $ sign will be there. Ex strings: Test_1,23_test_2,test3.

        String text = "$test_1$";
    Pattern p = Pattern.compile("$([A-Za-z0-9_])$");


    Matcher m = p.matcher(text);
    m.matches();
    if (m.find()) {
      System.out.println("Matched: " + m.group(1));
    } else {
      System.out.println("No match.");
    }

Szymon · Answer 1 · 2013-12-02T05:57:37.237

3

Your regex should be:

Pattern p = Pattern.compile("(\\$[A-Za-z0-9_]*\\$)");

edited Dec 02 '13 at 05:57

answered Dec 02 '13 at 05:47

Szymon

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It is giving compile time error. – Nishant Lakhara Dec 02 '13 at 05:56
Sorry, double backslash... – Szymon Dec 02 '13 at 05:58
thats ok but still it is not giving results. It is ouputting : No Match. The regex seems to be fine but still results are not as expected. – Nishant Lakhara Dec 02 '13 at 06:05
I got it . The user has called m.matches() before the if else statement. Its because of this results are not coming. – Nishant Lakhara Dec 02 '13 at 06:08
Yes, that's why I put brackets to capture a group. – Szymon Dec 02 '13 at 06:10

score 1 · Answer 2 · answered Dec 02 '13 at 06:00

1

You could simply do...

s.matches("\\$[a-zA-Z0-9_]*\\$")

answered Dec 02 '13 at 06:00

TheLostMind

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score 0 · Accepted Answer · answered Dec 02 '13 at 05:49

0

$ is a regex meta character and should be escaped, try this

    Pattern p = Pattern.compile("\\$([A-Za-z0-9_]+)\\$");

answered Dec 02 '13 at 05:49

Evgeniy Dorofeev

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It is giving results as no Match. – Nishant Lakhara Dec 02 '13 at 05:59
The user has called m.matches() before the if else statement. Its because of this results are not coming. – Nishant Lakhara Dec 02 '13 at 06:08

String pattern matching with regular expression in java

3 Answers3