CODEWITHSUNDEEP
javaregex
mliebelt
mliebelt

Reputation: 15525

Matching the last group of something in Java

I have the problem to define the regexpression (for a Java program), that gives me the last matching group of something. The reason for that is the conversion of some text files (here: the export of some wiki) to the new format of the new wiki.

For example, when I have the following text:

Here another include: [[Include(a/a-1)]]

The hierarchy of the pages is:

/a
  /a-1

The old wiki referenced the hierarchy name, the new wiki will only have the title of the page. The new format should look like:

{include:a-1}

Currently I have the following regular expression:

/\[\[Include\(([^\)]+)\)\]\]/

which matches from the example above a/a-1, but I need a regular expression that matches only a-1.

Is it possible to construct a regular expression for java that matches the last group only?

So for the following original lines:

[[Include(a)]]
[[Include(a/b)]]
[[Include(a/a-1)]]
[[Include(a/a-1/a-2)]]

I would like to match only

a
b
a-1
a-2

Upvotes: 0

Views: 73

Answers (1)

zx81
zx81

Reputation: 41838

This is the regex you're looking for. Group 1 has the text you want, see the captures pane at the bottom right of the demo, as well as the Substitutions pane at the bottom.

EDIT: per your request, replaced the [a-z0-9-] with [^/] (Did not update the regex101 demo as this regex, which I confirmed to work, breaks in regex101, which uses / as a delimiter, even when escaping the /. However here is another demo on regexplanet)

Search: 

\[\[Include\((?:[^/]+\/)*([^/]+)\)\]\]

Replace:

{include:$1}

How does it work?

After the opening bracket of the Include, we match a combination of characters such as a-1 (made of letters, dash and digits) followed by a forward slash, zero or more times, then we capture the last such combination of characters.

In the few languages that support infinite-width lookbehinds, we could match what you want without relying on Group 1 captures.

Upvotes: 1

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