How to get the index of Parentheses inside Parentheses in a String using Java

Question

I am giving input as a String s1= (RT)PO(Q(IT)); and want output as RTPO(QIT) as a String. If there is a parenthesis as a first character I want to remove that parentheses and its closing parentheses. Also, if there are 2 continuous parenthesis then remove the inside one. If I get indexes of these parentheses then I can remove them.

Can somebody help me with that? I am not good with Regex.

Answer 1

Regex is no use for this. You can use the indexOf(char ch, int fromIndex): ; and StringBuilder also have a deleteCharAt(int position) . So you just have to save the indexes of all opening and closing parenthesis in an ArrayList and delete them after. The subtility is of course, when you get a ( , then get the ) after, and look for the next ( only after the last ) (using the fromIndex parameter) and using some counter to remember how much parenthesis deep you are.

Answer 2

The following code answers to your first requirement ie

If there is a parenthesis as a first character I want to remove that parentheses and its closing parentheses.

***You can improvise the code for the rest

• in the below program i have implemented arraylist like a parser works .***

package mypackage;

import java.util.ArrayList; import java.util.Scanner;

public class BracketsModifier {

public static void main(String[] args) {

    Scanner scn=new Scanner(System.in);     
    System.out.println("enter the sample string ");     
    String sampleString=scn.next();
    int leftBracketCounter=0;
    int rightBrackerCounter=0;
    for(int i=0;i<sampleString.length();i++)
    {

        if(sampleString.charAt(i)=='(')
        {
            leftBracketCounter++;
        }
        else
            if(sampleString.charAt(i)==')')
            {

                rightBrackerCounter++;
                // System.out.println("first braket encounterd @ loc "+i);
            }
    }


if(leftBracketCounter==rightBrackerCounter)
{
    System.out.println("balanced String entered");

}
else {
    System.out.println("not a valid input");

}

    ArrayList< String>alist=new ArrayList<>();  
    int last_bracket_loc=0;

    for(int i=0;i<sampleString.length();i++)
    {
        if(sampleString.charAt(i)=='(')

        {
            alist.add("(");         
            }

        else if (sampleString.charAt(i)==')') {     
            int alist_size=alist.size();
            alist.remove(alist_size-1);
            last_bracket_loc=i;

        }           
    }

String temp = sampleString.substring(1,last_bracket_loc);
System.out.println("finally the data remained is "+ temp);

}
}

Answer 3

 var demo = "(RT)PO(Q(IT))"; var regex = /\\((\\w+)\\)/g; document.write(demo.replace(regex,"$1"));