Question

I thought to share this relatively smart problem with everyone here.
I am trying to remove unbalanced/unpaired double-quotes from a string.

My work is in progress, I might be close to a solution. But, I didn’t get a working solution yet. I am not able to delete the unpaired/unpartnered double-quotes from the string.

Example Input

string1=injunct! alter ego."
string2=successor "alter ego" single employer"  "proceeding "citation assets"

Output Should be

string1=injunct! alter ego.
string2=successor "alter ego" single employer  proceeding "citation assets"

This problem sound similar to
Using Java remove unbalanced/unpartnered parenthesis

Here is my code so far(it doesn’t delete all the unpaird double-quotes)

private String removeUnattachedDoubleQuotes(String stringWithDoubleQuotes) {
    String firstPass = "";

    String openingQuotePattern = "\\\"[a-z0-9\\p{Punct}]";
    String closingQuotePattern = "[a-z0-9\\p{Punct}]\\\"";

    int doubleQuoteLevel = 0;
    for (int i = 0; i < stringWithDoubleQuotes.length() - 3; i++) {
        String c = stringWithDoubleQuotes.substring(i, i + 2);
        if (c.matches(openingQuotePattern)) {
            doubleQuoteLevel++;
            firstPass += c;
        }
        else if (c.matches(closingQuotePattern)) {
            if (doubleQuoteLevel > 0) {
                doubleQuoteLevel--;
                firstPass += c;
            }
        }
        else {
            firstPass += c;
        }
    }

    String secondPass = "";
    doubleQuoteLevel = 0;
    for (int i = firstPass.length() - 1; i >= 0; i--) {
        String c = stringWithDoubleQuotes.substring(i, i + 2);
        if (c.matches(closingQuotePattern)) {
            doubleQuoteLevel++;
            secondPass = c + secondPass;
        }
        else if (c.matches(openingQuotePattern)) {
            if (doubleQuoteLevel > 0) {
                doubleQuoteLevel--;
                secondPass = c + secondPass;
            }
        }
        else {
            secondPass = c + secondPass;
        }
    }

    String result = secondPass;

    return result;
}

Answer 1

You could use something like (Perl notation):

s/("(?=\S)[^"]*(?<=\S)")|"/$1/g;

Which in Java would be:

str.replaceAll("(\"(?=\\S)[^\"]*(?<=\\S)\")|\"", "$1");