Java regex - replace substrings between delimiters with same substrings without delimiters

Question

I'm trying to figure out how to replace with Java 1.6 in strings like

hello ${world }!   ${txt + '_t'}<br/> ${do_not_replace

any substring identified between '${' and '}' with the same substring without these delimiters. So the output for the string above should be

hello world !   txt + '_t'<br/> ${do_not_replace

I identified a working pattern that allows me to replace the substrings with a fixed string

str.replaceAll('[${](.*?)}', '_')

and i know that i cannot use named groups with this version of Java.

Any suggestion for a simple solution to this problem are highly appreciated! Many thanks

"and i know that i cannot use named groups with this version of Java" Numbered groups are OK, though :) — dasblinkenlight, Apr 17 '13 at 10:40

Evgeniy Dorofeev · Accepted Answer · 2013-04-17 10:32:40Z

up vote 1 down vote accepted

try

    s = s.replaceAll("\\$\\{(.+?)}", "$1");

answered Apr 17 '13 at 10:32

Evgeniy Dorofeev
52.7k43781

Dasblinkenlight's solution is perfectly valid as well, so thank you both! – ilPittiz Apr 17 '13 at 14:11

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dasblinkenlight · Answer 2 · 2013-04-17 10:32:44Z

You can use capturing groups in the replacement string, like this:

str.replaceAll("[$][{](.*?)[}]", "$1");

Note that the character group [${] matches either a $ by itself or a { by itself, so you should rewrite it to match ${ together.

2 Answers 2