How to append String to StringBuffer variable in JAVA

Question

My code is as below. i need to add single quotes for each word in string with single quotes after appending DD to it.

public class Main
{
    public static void main(String[] args) {
        String ChkboxIds = "'a1b2c3','321cba','123abc'";
        String checkBoxId = null;
        String checkId = null;
        StringBuilder checkIDS = new StringBuilder("'");
        for(int i=0;i<=ChkboxIds.split(ChkboxIds, ',').length;i++){
            checkBoxId = "DD"+ChkboxIds.split(",")[i].replace("'","")+","+checkBoxId;
            checkId = checkBoxId.substring(0, checkBoxId.length() - 5);
            System.out.println("---PRINT---"+checkId);
            for(int j=0;j<i;j++){
                checkIDS..append('\'').append(checkId.split(",")).append('\'').append(',');
                System.out.println("---PRINT123----"+checkIDS);
            }
        }
    }
}

I have tried using StringBuffer too. please point your answers here. The output i get is some junk data while i need the words with dd attached at the start.

Expected output:'DDa1b2c3','DD321cba','DD123abc'

checkIDS..append('\'').append(checkId.split(",")).append('\'').append(','); beforethe first append there is 2 dots, delete one — ATP
– ATP, Commented Dec 28, 2021 at 9:26
Thanks for your comment but the issue is not the dot, it was a mistake in the code regarding the dot. and the junk data i am speaking about is : '[Ljava.lang.String;@d70c109',.... — Pratyusha Karra
– Pratyusha Karra, Commented Dec 28, 2021 at 10:21
Thanks for you comment.. i have got the answer required and marked a green tick for it — Pratyusha Karra
– Pratyusha Karra, Commented Dec 29, 2021 at 6:01

azro · Accepted Answer · 2021-12-28 09:51:40Z

1

Problem

issue at .append(checkId.split(",")) where you append an String[] so it's representation is it's hashcode
don't need a second loop, each word need one loop round, no inner loop needed
your split is wrong, you need ChkboxIds.split(","), you don't need with the same string as delimiter

Fix

You can do much more simpler than that

split on comma
remove quotes, append DD, add quotes
save at same place in array
join array with comma

String chkboxIds = "'a1b2c3','321cba','123abc'";

String[] splitted = chkboxIds.split(",");
String checkBoxId;

for (int i = 0; i < splitted.length; i++) {
    checkBoxId = "DD" + splitted[i].replace("'", "");
    splitted[i] = "'" + checkBoxId + "'";
}

String result = String.join(",", splitted);
System.out.println(result);
// 'DDa1b2c3','DD321cba','DD123abc'

Regex power

String chkboxIds = "'a1b2c3','321cba','123abc'";
String result = chkboxIds.replaceAll("'(\\w+)'", "'DD$1'");

edited Dec 28, 2021 at 9:51

answered Dec 28, 2021 at 9:46

azro

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1 Comment

Pratyusha Karra Over a year ago

Thanks for you answer its very helpful and i got the expected output

tquadrat · Accepted Answer · 2021-12-28 09:55:41Z

0

Try this:

var ids = Arrays.stream( ChkboxIds.split( "," ) ) // Separate the words
  .map( s -> s.replace( '\'', '' ) ) // Strip the single quotes
  .map( s -> "DD%s".formatted( s ) ) // Prepend with "DD"
  .collect( Collectors.joining( "','", "'", "'" ) );
System.out.println( ids );

Alternatively:

var ids = Arrays.stream( ChkboxIds.split( "," ) ) // Separate the words
  .map( s -> s.replaceFirst( "'", "'DD" ) ) // Replace the first single quote with the prefix
  .collect( Collectors.joining( "," ) );
System.out.println( ids );

Refer to the respective Javadoc for the details.

edited Dec 28, 2021 at 9:55

answered Dec 28, 2021 at 9:43

tquadrat

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Comments

Catherine O · Accepted Answer · 2021-12-28 10:22:37Z

For a simpler solution, you can try the code below.

public class Main
{
    public static void main(String[] args) {
        String ChkboxIds = "'a1b2c3','321cba','123abc'";
        //Replace all single quotes from the ChkboxIds, split them using comma delimiter, and store it to variable array
        String[] ChkboxIdsNew = ChkboxIds.replace("'","").split(","); 

        String checkIDS = ""; //String variable to be used to store the check ids

        //Loop through the ChkboxIdsNew array
        for (int i = 0; i < ChkboxIdsNew.length; i++) {
            //Only append comma if i is greater than zero
            if (i > 0) {
                checkIDS = checkIDS + ",";
            }
            //Concatenate the single quotes and prefix DD then append it to checkIDS
            checkIDS = checkIDS + "'DD" + ChkboxIdsNew[i] + "'";
        }


        System.out.println(checkIDS);
    }
}

Output:

cobp · Accepted Answer · 2021-12-28 10:41:03Z

0

Using regular expressions: If the single words doesnt contain additional single quotes:

    String ChkboxIds = "'a1b2c3','321cba','123abc'";
    ChkboxIds = ChkboxIds.replaceAll(",'",",'DD").replaceAll("^'","'DD");

Using iteration :

    String arChkBoxIds[]= ChkboxIds.split(",");
    StringBuilder checkIDS1 = new StringBuilder("");
    for (String chkBoxId:arChkBoxIds){
       
       checkIDS1.append("'DD").append(chkBoxId.substring(1)).append(",");
    }
    checkIDS1.setLength(checkIDS1.length()-1);
    System.out.println(checkIDS1);

answered Dec 28, 2021 at 10:41

cobp

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