How to use decimal format to hide trailing zero only in integer numbers

Question

I need format numbers like this:

23.0 -> 23
23.20 -> 23.20
23.00 -> 23
23.11 -> 23.11
23.2 -> 23.20
23.999 -> 24
23.001 -> 23
1345.999 -> 1346 // Edited the question to add this from the OP's comment

Here is my code: java:

  public static String toPrice(double number) {
         DecimalFormatSymbols formatSymbols = new DecimalFormatSymbols();
            formatSymbols.setGroupingSeparator(' ');
            DecimalFormat format = new DecimalFormat("#,###,###.##", formatSymbols);
            return format.format(number);
    
         }

kotlin:

fun Double.toPrice(): String =   DecimalFormat("#,###,###.##", DecimalFormatSymbols().apply {
                groupingSeparator = ' '
            }).format(this)

But for input 23.20 or 23.2 I get the result 23.2. This is wrong for me. I need 23.20. Which string pattern should I use to achieve this result? Please, help me.

Answer 1

Update

In case you need to format 1345.999 as 1346 (as mentioned in your comment), you can do so by adding a couple of extra steps in the original answer:

1. Format the number with the pattern, #,###,###.00 and then remove all commas so that it can be parsed back to double.
2. Parse the converted string into double and follow the rest of the solution as mentioned in the original answer.

Demo:

import java.text.DecimalFormat;
import java.text.NumberFormat;

public class Main {
    public static void main(String[] args) {
        System.out.println(getFromattedNumber(1234567.0));
        System.out.println(getFromattedNumber(1234567.20));
        System.out.println(getFromattedNumber(1234567.01));
        System.out.println(getFromattedNumber(1234567.00));
        System.out.println(getFromattedNumber(1345.999));
    }

    static String getFromattedNumber(double number) {
        NumberFormat format = new DecimalFormat("#,###,###.00");
        double num = Double.parseDouble(format.format(number).replace(",", ""));

        // Format for integer decimal numbers
        NumberFormat formatInt = new DecimalFormat("#,###,###");

        if ((int) num == num) {
            return formatInt.format(number);
        } else {
            return format.format(number);
        }
    }
}

Output:

1,234,567
1,234,567.20
1,234,567.01
1,234,567
1,346

Original answer

You will need to use two formats as shown below:

import java.text.DecimalFormat;
import java.text.NumberFormat;

public class Main {
    public static void main(String[] args) {
        System.out.println(getFromattedNumber(1234567.0));
        System.out.println(getFromattedNumber(1234567.20));
        System.out.println(getFromattedNumber(1234567.01));
        System.out.println(getFromattedNumber(1234567.00));
    }

    static String getFromattedNumber(double number) {
        // Format for integer decimal numbers
        NumberFormat format1 = new DecimalFormat("#,###,###");

        // Format for non-integer decimal numbers
        NumberFormat format2 = new DecimalFormat("#,###,###.00");

        if ((int) number == number) {
            return format1.format(number);
        } else {
            return format2.format(number);
        }
    }
}

Output:

1,234,567
1,234,567.20
1,234,567.01
1,234,567