Regex expression for fetching values inside quotation marks-CodePudding

Been trying different expressions to fetch string inside single quotation marks. As of now I was using a simple regex : '(.*?)'

But this one fails on particular scenario when there are nested quotation marks in string.

Example 1: A = "someMethod('abc','de'f','ghi')" Matching Group 1 : abc Group 2 : de'f Group 3 : ghi

Any help is much appreciated.

Not very expert in creating regular expressions but tried a few solutions currently present on StackOverflow. Didn't work as I expected.

CodePudding user response：

.*? is called Reluctant Quantifiers it try eat the char of your string one by one till it find a match but if you used .* it's greedy match which will eat your whole string then drop one by one till it find match

so your regex be : '(.*)'

you can use the boundry option for your regex

so it be like '(.*?)'$

check this one for extra explanation https://dev.java/learn/regex/quantifiers/#greedy-reluctant-possessive

and of course you can check the whole tutorial https://dev.java/learn/regex/

and you can try your regex here https://regex101.com/ make sure to choose the java flavor

hope that help and have a nice day :)

CodePudding user response：

If your single quoted substrings are always separated by , or are enclosed by parenthesis, you can lookahead for these two characters in the regex, '.*?'(?=[,\)]).

Demo:

class Main {
    public static void main(String[] args) {
        String str = "someMethod('abc','de'f','ghi')";
        Matcher matcher = Pattern.compile("'.*?'(?=[,\\)])").matcher(str);
        while (matcher.find())
            System.out.println(matcher.group());
    }
}

Output:

'abc'
'de'f'
'ghi'