Question

I am not good in regular expressions and I need help in replacing the string.

String str = "Name_XYZ_";
       str = "XYZ_NAME_";

So how can I replace "Name_" or "_NAME_" from above two strings with empty string?
The conditions are "Name" can be in any case and it can be at index 0 or at any index but preceded by "_".

So far I tried,

String replacedString = str.replaceAll("(?i)Name_", ""); // This is not correct.

This is not the homework. I am working on XML file that needs such kind of processing.

Answer 1

String replacedString = str.replaceAll("(?i)(?:^|_)name_", "");

You were close. What you have to do is either anchor name to the beginning of the string (with ^) or require an underscore there. I also changed Name to name, because why mix lower and upper case, if you are treating the pattern case-insenstively anyway. Note that ?: is just an optimization (and a good practice). It suppresses capturing which you don’t need in this case.

If you want to improve your regex skills, I can highly recommend this tutorial.