CODEWITHSUNDEEP
javanumber-formatting
Pawan
Pawan

Reputation: 32331

How to format a double with variable amount of decimal digits

I was working on a task where I was struck handling a negative scenario mentioned below

If the Value is less than 1 then I want to format (add) 4 decimal points to it .

For example if value is 0.4567 then I need 0.4567

Or else if the value is greater than 1 format with only 2 digits.

For example if value is 444.9 then I need 444.90

Everything above mentioned is working fine, but struck on this below condition

That is if the value is less than 1 and it ends as zeros (0.1000 , 0.6000) , It makes no sense to print 0.2000, so in that case I want the output to be only as 0.20

This is my program below 

package com;
import java.text.DecimalFormat;
public class Test {
    public static void main(String args[]) {
        try {
            String result = "";
            Test test = new Test();
            double value = 444.9;
            if (value < 1) {
                result = test.numberFormat(value, 4);
            } else {
                result = test.numberFormat(value, 2);
            }
            System.out.println(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public String numberFormat(double d, int decimals) {
        if (2 == decimals)
            return new DecimalFormat("#,###,###,##0.00").format(d);
        else if (0 == decimals)
            return new DecimalFormat("#,###,###,##0").format(d);
        else if (3 == decimals)
            return new DecimalFormat("#,###,###,##0.000").format(d);
        else if (4 == decimals)
            return new DecimalFormat("#,###,###,##0.0000").format(d);
        return String.valueOf(d);
    }

}

Upvotes: 6

Views: 5349

Answers (2)

Dariusz
Dariusz

Reputation: 22271

Just make a string with four digits and check for trailing zeros. If there are two zeros or less, remove them. Otherwise, leave it as it is.

result = test.numberFormat(value, 4);
if (result.endsWith("00")) {
  result=result.substring(0, result.length()-2);
} else if (result.endsWith("0")) {
  result=result.substring(0, result.length()-1);
}

It may not be optimal, but it's easy to read and maintain.

Upvotes: 0

chetan
chetan

Reputation: 2896

use # if you want to ignore 0 in 3rd and 4th decimal places

new DecimalFormat("#,###,###,##0.00##").format(d)

Upvotes: 6

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