Develop Reference

Format To Display the Thousand Part of a Double Value

For example; I have the next Double value: Double number = 53149000;
And I want to display it like this, with a format: 53,149
Is this possible...?
Thanks in Advance...

You can use the String.format method after dividing your value by 1000
double number = 53149000;
System.out.println(String.format("%,.0f", number/1000));

I suggest you use the DecimalFormat object to achieve that. For example:
DecimalFormat decimalFormat = new DecimalFormat("###,###");
System.out.println(decimalFormat.format(number/1000));
It prints 53,149 as expected.
I hope it helps.

How to convert the 6020494385.89982 string value to double

How to convert the "6020494385.89982" string value to a double?
String ss = "6020494385.89982";
double dd = Double.parseDouble(String.valueOf(ss));
System.out.println(dd);
I am getting the output as
6.02049438589982E9 but I want 6020494385.89982 as double value.

Use of a DecimalFormatobject should do the trick
String ss = "6020494385.89982";
double dd = Double.parseDouble(String.valueOf(ss));
System.out.println(new DecimalFormat("#0.00000").format(dd));
Or you can use System.out#printf()
System.out.printf("%.5f", dd);
Because System.out.println has a particular way of working with double precisions that will not work in this particular case for example.

The number is correct. 6.02049438589982E9 is just the scientific notation, which is the default when you print a double. If you want the non-scientific notation, you could just use printf instead of println:
System.out.printf("%f\n", dd);

6.02049438589982E9 is the same as 6020494385.89982
6.02049438589982E9 = 6.02049438589982 X 10^9
the value stored in the double is 6020494385.89982 However, when you print it out, it represents in this format: 6.02049438589982E9

You do not need to convert into double if in the end you want the representation in the same format as the current value of ss variable.
However if you need to convert for some other purpose and then need to show in that format later/else where you can use DecimalFormat as others have suggested.

Multiply with two Decimal Place - Java

multiply the double Type number, from the output need to taken with two Decimal Place
double creditCardPercentage = 0.03;
String renewalEventAmount = "2144.60";
double expectedRenewalAmount = 0;
expectedRenewalAmount = Double.parseDouble(renewalEventAmount) * creditCardPercentage;
the output for the expectedRenewalAmount is 64.338, then how can we format the above output with two decimal
Expected:
64.33

You should use the BigDecimal class because it has built-in handling for floating point precision:
BigDecimal creditCardPercentage = new BigDecimal(0.03);
String renewalEventAmountString = "2144.60";
BigDecimal renewalEventAmount = new BigDecimal(renewalEventAmountString);
BigDecimal expectedRenewalAmount = renewalEventAmount.multiply(creditCardPercentage);
expectedRenewalAmount = expectedRenewalAmount.setScale(2, BigDecimal.ROUND_HALF_DOWN);
System.out.println(expectedRenewalAmount); // prints 64.33
One of the advantages of using BigDecimal to handle the formatting is that it allows you to separate your code from your business logic, i.e. rounding down to 2 decimal places, from the view code which outputs the result to the user.

You could use NumberFormat.getNumberInstance().format(expectedRenewalAmount) which will use the system properties to format the value. You can also modify the NumberFormat, specifying the number of decimal places if you want.
Or you could use System.out.printf or String.format to format the value as well...
String value = String.format("%.2f", expectedRenewalAmount);

A couple answers have suggested printf; but if you don't want to print the answer right away, you can use String.format the same way:
String formattedString = String.format("%.2f", expectedRenewalAmount);
and now you can print out the result if you want, or you can display it in a Swing text window or change all the zeros to happy faces or do whatever else you like with the resulting string, which you can't do with printf.

You can use the printf() function with %f:
System.out.printf("%.2f", expectedRenewalAmount);
Here you can find a beautiful printf format cheat sheet by Alvin Alexander that might help you (and hopefully others) a lot.

Try this while printing:
System.out.printf("%.2f", expectedRenewalAmount);

You can use
DecimalFormat df = new DecimalFormat("#.00");
double creditCardPercentage = 0.03;
String renewalEventAmount = "2144.60";
double expectedRenewalAmount = 0;
expectedRenewalAmount = df.format(Double.parseDouble(renewalEventAmount) * creditCardPercentage);

you can use minimumFractionDigit to 0
public class Test {
public static void main(String[] args) {
System.out.println(format(14.0184849945)); // prints '14.01'
System.out.println(format(13)); // prints '13'
System.out.println(format(3.5)); // prints '3.5'
System.out.println(format(3.138136)); // prints '3.13'
}
public static String format(Number n) {
NumberFormat format = DecimalFormat.getInstance();
format.setRoundingMode(RoundingMode.FLOOR);
format.setMinimumFractionDigits(0);
format.setMaximumFractionDigits(2);
return format.format(n);
}
}
please find below reference link.
Java: Use DecimalFormat to format doubles and integers but keep integers without a decimal separator

Formatting double to 2 decimals doesn't work

I want to round this double:
3.499999999999999
to:
3.50
And I already used these two methods:
DecimalFormat df = new DecimalFormat("0.00");
double result = Double.valueOf(df.format(input));
System.out.println(answer);
and
public double round(double input)
{
int decimalPlace = 2;
BigDecimal bd = new BigDecimal(input);
bd = bd.setScale(decimalPlace,BigDecimal.ROUND_UP);
return (bd.doubleValue());
}
But It keeps printing:
3.5
Does anyone have a solution for this? Because I really think that this should work. Thanks for your help.

Your first solution is really, really close. Just do this:
DecimalFormat df = new DecimalFormat("0.00");
System.out.println(df.format(input));
The reason your version doesn't work is that you're taking the input double, formatting it as a String with 2dp, but then converting it back to a double. System.out.println is then printing the double as it always would, with no special decimal-place rules.

You can use the printf formatting which may be simpler.
System.out.printf("%.2f%n", 3.5);
prints
3.50

Did you try replacing the 0's with #'s?
DecimalFormat df = new DecimalFormat("#.##");
System.out.println(df.format(input));
According to here the # will be resolved to 0 if the digit is absent

You can use Precision class of apache commons-math
double result = Precision.round(3.499999999999999, 2);

convert very small double to a String

I have a very small number and I want to convert it to a String with the full number, not abbreviated in any way. I don't know how small this number can be.
for example, when I run:
double d = 1E-10;
System.out.println(d);
it shows 1.0E-10 instead of 0.000000001.
I've already tried NumberFormat.getNumberInstance() but it formats to 0. and I don't know what expression to use on a DecimalFormat to work with any number.

Assuming that you want 500 zeroes in front of your number when you do:
double d = 1E-500;
then you can use:
double d = 1E-10;
NumberFormat nf = NumberFormat.getInstance();
nf.setMaximumFractionDigits(Integer.MAX_VALUE);
System.out.println(nf.format(d));

You can set the maximum and minimum number of digits in the fraction of a numberformatter with setMinimumFractionDigits and setMaximumFractionDigits. that should fix the problem.

You can do it with BigDecimals in Java 5 using:
System.out.println(new java.math.BigDecimal(Double.toString(1E-10)).stripTrailingZeros().toPlainString());
Note that if you have the double value as a String in the first place, you would be better off using:
System.out.println(new java.math.BigDecimal("1E-10").toPlainString());
... as explained in the BigDecimal javadocs.

Have a look at: http://java.sun.com/docs/books/tutorial/i18n/format/decimalFormat.html#numberpattern
I think the format "0.####" might work.