Double decimal formatting in Java

Question

I\'m having some problems formatting the decimals of a double. If I have a double value, e.g. 4.0, how do I format the decimals so that it\'s 4.00 instead?

Answer 1

One of the way would be using NumberFormat.

NumberFormat formatter = new DecimalFormat("#0.00");     
System.out.println(formatter.format(4.0));

Output:

4.00

Answer 2

There are many way you can do this. Those are given bellow:

Suppose your original number is given bellow:

 double number = 2354548.235;

Using NumberFormat:

NumberFormat formatter = new DecimalFormat("#0.00");
    System.out.println(formatter.format(number));

Using String.format:

System.out.println(String.format("%,.2f", number));

Using DecimalFormat and pattern:

NumberFormat nf = DecimalFormat.getInstance(Locale.ENGLISH);
        DecimalFormat decimalFormatter = (DecimalFormat) nf;
        decimalFormatter.applyPattern("#,###,###.##");
        String fString = decimalFormatter.format(number);
        System.out.println(fString);

Using DecimalFormat and pattern

DecimalFormat decimalFormat = new DecimalFormat("############.##");
        BigDecimal formattedOutput = new BigDecimal(decimalFormat.format(number));
        System.out.println(formattedOutput);

In all cases the output will be: 2354548.23

Note:

During rounding you can add RoundingMode in your formatter. Here are some rounding mode given bellow:

    decimalFormat.setRoundingMode(RoundingMode.CEILING);
    decimalFormat.setRoundingMode(RoundingMode.FLOOR);
    decimalFormat.setRoundingMode(RoundingMode.HALF_DOWN);
    decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
    decimalFormat.setRoundingMode(RoundingMode.UP);

Here are the imports:

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

Answer 3

new DecimalFormat("#0.00").format(4.0d);

Answer 4

double d = 4.0;
DecimalFormat nf = DecimalFormat.getInstance(Locale.ENGLISH);
System.out.println(nf.format("#.##"));

Answer 5

Use String.format:

String.format("%.2f", 4.52135);

As per docs:

The locale always used is the one returned by Locale.getDefault().

Answer 6

You could always use the static method printf from System.out - you'd then implement the corresponding formatter; this saves heap space in which other examples required you to do.

Ex:

System.out.format("%.4f %n", 4.0); 

System.out.printf("%.2f %n", 4.0); 

Saves heap space which is a pretty big bonus, nonetheless I hold the opinion that this example is much more manageable than any other answer, especially since most programmers know the printf function from C (Java changes the function/method slightly though).