ArrayList to String with separated by Comma

Question

I have an ArrayList and I want to output completely as a String with separated by comma.

My code is

ArrayList<String> list = new ArrayList<String>();
list.add("one");
list.add("two");
list.add("three");

String listString = "";

for (String s : list)
{
    listString += s + ",";
}

System.out.println(listString);

But the output is one,two,three, and i want one,two,three without using replace method.

I am using JAVA

`listString += (listString.isEmpty() ? "" : ",") + s;`. Note that you should use a `StringBuilder` rather than direct concatenation. — Andy Turner, May 04 '16 at 11:58
String class has a method called join, so that you don't have to iterate through the collection to join the elements. [Here](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#join-java.lang.CharSequence-java.lang.Iterable-) is the doc — Rahul Sharma, May 04 '16 at 12:05

score 5 · Answer 1 · answered May 04 '16 at 12:04

5

Using Java 8:

List<String> list = Arrays.asList(array);
String joinedString = String.join(",", list);

answered May 04 '16 at 12:04

Krishnanunni P V

689
5
18
32

score 1 · Accepted Answer · answered May 04 '16 at 12:00

In Java 8+ you could use a StringJoiner (and you can use Arrays.asList(T...) to initialize your List). Something like,

List<String> list = Arrays.asList("one", "two", "three");
StringJoiner sj = new StringJoiner(",");
for (String s : list) {
    sj.add(s);
}
System.out.println(sj.toString());

Output is (as requested)

one,two,three

score 0 · Answer 3 · answered May 04 '16 at 12:00

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        ArrayList<String> list = new ArrayList<String>();
        list.add("one");
        list.add("two");
        list.add("three");

        String listString = "";

        for (int i=0;i<list.size()-1;i++)
            listString += list.get(i) + ",";

        System.out.println(listString+list.get(list.size()-1));
    }
}

Output:

one,two,three

http://ideone.com/PkAOOq

score 0 · Answer 4 · answered May 04 '16 at 12:00

0

Just use String.substring. Here you go:

listString = listString.substring(0, listString.length() - 1);

answered May 04 '16 at 12:00

Adnan Isajbegovic

2,227
17
27

score 0 · Answer 5 · answered May 04 '16 at 12:02

You can use java.util.StringJoiner for this, instead of a List:

    StringJoiner joiner = new StringJoiner(",");
    joiner.add("one");
    joiner.add("two"),
    joiner.add("three");

    String listString = joiner.toString();

If you are not using Java8, then consider using StringBuilder. Then your final string can be:

System.out.println(listString.substring(0, listString.length() - 1));

score 0 · Answer 6 · answered May 04 '16 at 12:05

0

For a pre Java 8 solution, since the default toString() gives you [one, two, three].

String s = list.toString();
s = s.substring(1, s.length()-1);

answered May 04 '16 at 12:05

Kayaman

72,141
5
83
121

score 0 · Answer 7 · answered May 04 '16 at 12:25

0

try

list.toString().replace("[", "").replace("]", "");

answered May 04 '16 at 12:25

Muhammad Suleman

2,892
2
25
33

ArrayList to String with separated by Comma

7 Answers7