regex for finding a particular file

Question

I want to match a file name as "abc (1).xyz" or "abc (2).xyz" or "abc (3).xyz" and so on, in which abc and xyz (extension) is fixed. Besides, the space+(number) part is optional, i.e. the abc.xyz is also valid.

I have tried the below code, but it didn't returns the success response:

String regex = "abc\\s([0-9])\\.xyz";
        Pattern mather = Pattern.compile(regex);

        if (mather.matcher(fileName).matches()) {
            return true;
        } else {
            return false;
        }

Please suggest any solution for the same. Thanks in advance.

If the parentheses are literal, use `abc\\s\$[0-9]+\$\\.xyz"` — Wiktor Stribiżew, Dec 05 '17 at 10:11
Thanks Wiktor, but is there any option to make brackets and digits optional in regex, as it could match "abc.ini" also? — Sanat Pandey, Dec 05 '17 at 12:24
Glad it worked for you. Please also consider upvoting if my answer proved helpful to you (see [How to upvote on Stack Overflow?](http://meta.stackexchange.com/questions/173399/how-to-upvote-on-stack-overflow)). — Wiktor Stribiżew, Dec 08 '17 at 00:14

score 0 · Accepted Answer · answered Dec 06 '17 at 11:02

You may use

String regex = "abc(?:\\s+\\([0-9]+\\))?\\.xyz";

It will match:

abc - abc
(?:\\s+\$[0-9]+\$)? - an optional sequence of:
- \\s+ - 1+ whitespace chars
- \$ - a (
- [0-9]+ - 1+ digits
- \$ - a )
\\.xyz - a .xyz substring.

Since you are using Matcher#matches() method, the whole string match is required (as if the whole pattern was enclosed with ^ and $ anchors, "^abc(?:\\s+\$[0-9]+\$)?\\.xyz$").

regex for finding a particular file

1 Answers1