How do I convert this array into list in my specific case?

Question

I have iterated through an array B . Checked whether there are elements that are common in an arrayList A . Then removed those elements and printed out A as an array.

But my question is how can I print out A (in my program it's System.out.println(crIss.get(m)); ) as an arrayList (Just a list of element without [] bracket) instead of an array?

This is the complete code I am working on:

package issuetracking;

import java.util.*;

public class IssueTrackingObject {

    ArrayList<String> crIss = new ArrayList<String>();

    Scanner input = new Scanner(System.in);
    boolean crIss_bool;
    int numOfSolvedIss;
    private String[] solvedIss;

    //lets user create some issues and add them into an arrayList
    public void createIssue() {
        System.out.println("Enter 5 issues: ");

        for (int i = 0; i < 5; i++) {
            System.out.println("Issue " + (i + 1 + ": "));
            crIss_bool = crIss.add(input.nextLine());
        }

    }
//Let user mark some issues as solved (which are already in the list that the user has just created)

    public void solvedIssue() {
        System.out.println("How many solved issue you have(Must be less than 5): ");
        numOfSolvedIss = input.nextInt();

        solvedIss = new String[numOfSolvedIss];

        for (int k = 0; k < numOfSolvedIss; k++) {
            System.out.print("Enter solved issue(REMEMBER THAT THE SOLVED ISSUE MUST BE FROM ONE OF THEM YOU ALREADY HAVE CREATED)no. " + (k + 1) + ": ");

            solvedIss[k] = input.next();
        }

    }

    public void printUnsolvedIssue() {

for(int m=0; m<solvedIss.length;m++){
      crIss_bool = crIss.remove(solvedIss);

    System.out.println(crIss.get(m));   
}


    }


    public void printSolvedIssue() {
        System.out.println("");
        System.out.println("LIST OF SOLVED ISSUE:");

        for (int l = 0; l < solvedIss.length; l++) {
            System.out.printf("%s ", solvedIss[l]);
        }

    }

}

main class:

package issuetracking;

import java.util.*;

public class IssueTracking {

    static Scanner input = new Scanner(System.in);

    public static void main(String[] args) {
        IssueTrackingObject its = new IssueTrackingObject();

        System.out.println("                            WELCOME TO ISSUE TRACKING SYSTEM!\n\n");
        System.out.println("Choose from menu: ");
        System.out.println("1. Create new issue\n2. Mark issue(s) as solved\n"
                + "3. View solved issue(s)\n4. View unsolved issue(s)");
        System.out.println("Enter you choise:");
        //String userChoise = input.next();
        //switch-case

        while (true) {
            String userChoise = input.next();

            switch (userChoise) {
                case "1":
                    //System.out.println("Enter 5 issues: ");
                    //call appropriate issue
                    its.createIssue();
                    break;
                case "2":
                    //System.out.println("Mark solved issues (You must enter at least one issue): ");
                    //call appropriate issue
                    its.solvedIssue();
                    break;
                case "3":
                    System.out.println("Solved issue: ");
                    //call appropriate method
                    its.printSolvedIssue();
                    break;

                case "4":
                    System.out.println("Usolved issue: ");
                    //call appropriate issue
                    its.printUnsolvedIssue();
                    break;
                default:
                    System.out.println("Invalid input");
                    break;

            }

        }

    }

}

Answer 1

The printing behavior you are exprienging is becasue when you print an object like an ArrayList , Java calls the Class's .toString() method. ArrayList.toString() is inherited from AbstractCollection.toString() which documentation can be found here .

My suggestion to change this behavior is to create a sepreate Print function similar to the following:

public void printList(ArrayList<String> list)
{
     for(String str : list)
     {
          System.out.print(str+" ");
     }
     System.out.println();
}

Then call this function in place of your print statement:

printList(crIss);

Note that this print will print each element of your List on one line, separated by a space.

Answer 2

There are several ways to do this. I'll show you three:

1. Storing the data in a String and remove the unrequired characters:

    String tmp = crIss.toString(); tmp = tmp.substring(1, tmp.length() - 1); System.out.println(tmp); 

2. Similar to approach above but using replace :

    String tmp = crIss.toString().replace('[', '\\0').replace(']', '\\0'); System.out.println(tmp); 

3. Iterating through your List and storing the values in StringBuilder :

    StringBuilder sb = new StringBuilder(); for (String string : crIss) { sb.append(string).append(", "); } sb.remove(sb.length() - 2, sb.length()); System.out.println(sb.toString()); 

Answer 3

Just iterate through crIss and print each item in it, followed by the desired delimiter. In this example, I will separate the items with ", ".

public void printUnsolvedIssue() {

   for(int m=0; m<solvedIss.length;m++){
       crIss.remove(solvedIss[i]);
   }

   for(int i = 0; i < crIss.size(); i++) {
       System.out.print(crIss.get(i));
       // only print the delimiter if it isn't the last item in the list
       if(i < crIss.size() - 1) {
           System.out.print(", ");
       }
   }
}

Also notice I changed the crIss.remove(solvedIss) part to crIss.remove(solvedIss[i]) . This way it will remove each item in solvedIss .