Remove trailing comma from comma-separated string

Question

I got String from the database which have multiple commas (,) . I want to remove the last comma but I can\'t really find a simple way of doing it.

Answer 1

You can do something like using join function of String class.

import java.util.Arrays;
import java.util.List;

public class Demo {

    public static void main(String[] args) {
        List<String> items = Arrays.asList("Java", "Ruby", "Python", "C++");
        String output = String.join(",", items);
        System.out.println(output);
    }

}

Answer 2

This method is in BalusC's StringUtil class. his blog

i use it very often and will trim any string of any value:

/**
 * Trim the given string with the given trim value.
 * @param string The string to be trimmed.
 * @param trim The value to trim the given string off.
 * @return The trimmed string.
 */
public static String trim(String string, String trim) {
    if (string == null) {
        return null;
    }

    if (trim.length() == 0) {
        return string;
    }

    int start = 0;
    int end = string.length();
    int length = trim.length();

    while (start + length <= end && string.substring(
            start, start + length).equals(trim)) {
        start += length;
    }
    while (start + length <= end && string.substring(
            end - length, end).equals(trim)) {
        end -= length;
    }

    return string.substring(start, end);
}

ex:

trim("1, 2, 3, ", ", ");

Answer 3

Or something like this:

private static String myRemComa(String input) { 
        String[] exploded = input.split(",");
        input="";
        boolean start = true;
        for(String str : exploded) {

         str=str.trim();
         if (str.length()>0) {
             if (start) {
                 input = str;
                    start = false;
                } else {
                    input = input + "," + str;
                }
         }
        }

        return input;
    }

Answer 4

You can try with this, it worked for me:

if (names.endsWith(",")) {
    names = names.substring(0, names.length() - 1);
}

Or you can try with this too:

string = string.replaceAll(", $", "");