Applying RegularExpression on a String

Question

Hi guys,
I have a string like "(a>5) AND (B>8) OR (C+7)"
Now, i want to get that AND and OR.
Is there any simple way to get that using regular expression.
Is it possible to apply a regular expression that retuns the string that is between ")" and "(".
if so, pls tell what is that regular expression?
--Subbu                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

codingMonkey wrote:
[\\){1}\\.*\\({1}]
There are several problems with this regex. First, the square brackets define a character class, which matches precisely one of the characters within the brackets. Thus, this regex will match one of the characters, '(', ')', '{', '}', '.', '*', or '1'. (Within a character class, most regex metacharacters lose their special meanings, so the braces match literal braces even though they aren't escaped.)
By the way, there is never any reason to use "{1}" in a regex. It's legal, but it's just noise; everything matches exactly once unless you specify otherwise.
Second, if you remove the square brackets, you end up with a regex that matches from the first close-parenthesis to the last open-parenthesis, because the '*' quantifier is greedy. If you don't want it to match all of ") AND (B>8) OR (" in one go, you need to make the quantifier non-greedy (or reluctant) by appending '?' to it. Or you could avoid the issue by using a negated character class, like Darryl did.
Finally, your regex matches the parentheses, when the OP only wanted to match what lies between them. Darryl showed one way to accomplish that, by using lookarounds. Another way is to use capturing groups: String str = "(a>5) AND (B>8) OR (C+7)";
Pattern p = Pattern.compile("\\)(.*?)\\(");
Matcher m = p.matcher(str);
while (m.find())
  System.out.println(m.group(1));
}