Java Program to Convert a List of String to Comma Separated String

In this article, we will understand how to convert a list of string to comma separated string. A list is an ordered collection that allows us to store and access elements sequentially. It contains the index-based methods to insert, update, delete and search the elements. It can also have the duplicate elements.

Below is a demonstration of the same −

Suppose our input is −

Input list: [Java, Scala, Python]

The desired output would be −

The list with comma separated elements: Java, Scala, Python

Algorithm

Step 1 - START
Step 2 - Declare a List namely input_list.
Step 3 - Define the values.
Step 4 - Use the built in function .join() to add comma in between the elements of the object.
Step 5 - Display the result
Step 6 - Stop

Example 1

Here, we bind all the operations together under the ‘main’ function.

import java.util.*;
public class Demo {
   public static void main(String args[]){
      List<String> input_list =
      new ArrayList<>( Arrays .asList("Java", "Scala", "Python"));
      System.out.println("The input_list is defined as: " + input_list);
      String string = String.join(", ", input_list);
      System.out.println("The list with comma separated elements: " + string);
   }
}

Output

The input_list is defined as: [Java, Scala, Python]
The list with comma separated elements: Java, Scala, Python

Example 2

Here, we encapsulate the operations into functions exhibiting object oriented programming.

import java.util.*;
public class Demo {
   static void add_comma(List<String> input_list){
      String string = String.join(", ", input_list);
      System.out.println("The list with comma separated elements: " + string);
   }
   public static void main(String args[]){
      List<String> input_list =
      new ArrayList<>( Arrays .asList("Java", "Scala", "Python"));
      System.out.println("The list is defined as: " + input_list);
      add_comma(input_list);
   }
}

Output

The list is defined as: [Java, Scala, Python]
The list with comma separated elements: Java, Scala, Python