Java Regex Find/replace

Question

I have the following string

aaaa#include(soap1.xml)bbbb #include(soap2.xml)cccc #include(soap2.xml)

I want to find all occurrences of #include([anyfilename]) where [anyfilename] varies.

I have the regex (?<=#include\()(.*?)(?=\)*\)) which matches [anyfilename] but then performing a replace using this leaves behind there #include()

Can someone suggest show me how to find/replace the entire #include([anyfilename])?

• Wiktor Stribiżew: What is the expected result? Please add your current code to the answer. Do you want to remove #include(soap2.xml) and #include(soap1.xml)?
• Pshemo: "performing a replace using this leaves behind there #include()" well, look-around mechanisms are zero-length (they are not included in match - the one you want to replace) so that behaviour is expected. What else did you expect and why?
• Wiktor Stribiżew: I shared a wrong link :) I will post an answer.
• Andreas: \)*\) is the same as \)+, which is clearer on intent. As for that, why match multiple close-parenthesis?
• Andreas: Right now, the positive look-behind/-ahead will check for existence, without being included. If you want to include them in the match, just drop the look-behind/-ahead parts. And since your capture group would then equal the entire match, there's no need for capturing. So that would result in: #include\(.*?\)+ (see regex101 for result).

Answer 1

You may use the following regex:

#include\(([^)]*)\)

See the regex demo

I replaced lookarounds (that are zero-width assertions and do not consume text, do not return it in the match value) with consuming equivalents.

The regex breakdown:

• #include\( - match a sequence of literal symbols #include(
• ([^)]*) - Group 1 (we'll refer to the value inside the group with matcher.group(1)) matching zero or more characters other than )
• \) - match a literal )

The same pattern can be used to retrieve the filenames, and remove whole #include()s from the input.

IDEONE demo:

String str = "aaaa#include(soap1.xml)bbbb#include(soap2.xml)cccc";
String p = "#include\\(([^)]*)\\)";
Pattern ptrn = Pattern.compile(p);
Matcher matcher = ptrn.matcher(str);
List<String> arr = new ArrayList<String>();
while (matcher.find()) {
 arr.add(matcher.group(1)); // Get the Group 1 value, file name
}
System.out.println(arr); // => [soap1.xml, soap2.xml]
System.out.println(str.replaceAll(p, "")); // => aaaabbbbcccc