Java RegEx backreference not working

Question

In java I tried to replace .JPG.json part with .JPG, saving letter case ( sometimes it maybe .jpg.json)

My Code :

String Path="MyImage.JPG.json";
Result=Path.replaceFirst("/(.jpg)\\.json/i","$1");

But it returns : MyImage.JPG.json

Instead of: MyImage.JPG

Avinash Raj · Accepted Answer · 2015-01-20 08:19:20Z

1

You need to remove the / slashes. In java, you don't need to include / as a regex delimiter. And also you must need to escape the dots. To do a case-insensitive match, add (?i) modifier at the first.

Path.replaceFirst("(?i)(\\.jpg)\\.json", "$1");

OR

You could use lookbehind assertion also.

Path.replaceFirst("(?i)(?<=\\.jpg)\\.json", "");

(?<=\\.jpg) Asserts that the string going to be matched must be preceded by .jpg. If yes then match only the following .json string. Replacing the matched .json string with an empty string will give you the desired output.

edited Jan 20, 2015 at 8:19

answered Jan 20, 2015 at 8:08

Avinash Raj

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Jens · Accepted Answer · 2015-01-20 08:12:14Z

0

Try this command. It should work for you:

Path.replaceFirst("(?i)(\\.jpg)\\.json","$1")

answered Jan 20, 2015 at 8:12

Jens

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