Question

Is there any way to truncate the negative sign when the result returns zero; while using decimal format?

DecimalFormat df = new DecimalFormat("#,##0.0");
df.setRoundingMode(RoundingMode.HALF_UP);
formattedValue = df.format("-0.023");

The above code returns -0.0 . Is there any way by which it will return only 0.0? However, I want to retain the negative sign when the result is a negative number.

Answer 1

I don’t think there’s a way of doing it just with DecimalFormat, but this one-liner takes care of the problem:

formattedValue = formattedValue.replaceAll( "^-(?=0(\\.0*)?$)", "");

It removes (replaces with "") the minus sign if it’s followed by 0-n characters of "0.00000...", so this will work for any similar result such as "-0", "-0." or "-0.000000000"

Here’s some test code:

public static void main(String[] args) {
    System.out.println(format(-0.023));
    System.out.println(format(12.123));
    System.out.println(format(-12.345));
    System.out.println(format(-0.123));
    System.out.println(format(-1.777));
}

public static String format(double number) {
    DecimalFormat df = new DecimalFormat("#,##0.0");
    df.setRoundingMode(RoundingMode.HALF_UP);
    String formattedValue = df.format(number);
    formattedValue = formattedValue.replaceAll("^-(?=0(\\.0*)?$)", "");
    return formattedValue;
}

Output (as expected):

0.0
12.1
-12.3
-0.1
-1.8