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How to round numbers, remove "E"s from them and remove decimal points from whole numbers?

I have a crypto portfolio made, but the long percentage numbers or the "E"s instead of big numbers really tear up the design, like in this example:
How to fix them (round up to 2 decimal digits, remove E, remove .0 from 5)?

Try this:
Math.round(number * 100.0) / 100.0;
You can find plenty of other ways if you search.

Using the Double constructor, you can turn all of those strings into doubles.
String someNumberString = "1.2E5";
Double dNum = new Double(someNumberString);
You can do rounding as such:
double rounded = (Math.round(dNum * ROUND_TO_OFFSET) / ROUND_TO_OFFSET)
where ROUND_TO_OFFSET specifies the digit to round to. E.g. ROUND_TO_OFFSET= 100 rounds to the nearest 0.01. This has a disadvantage though. Math.round returns a long, so if your dNum * ROUND_TO_OFFSET produces a number that is larger or smaller than a long can hold, it will not work correctly.
You can format any double into a nice, easy to read format with the DecimalFormat class.
DecimalFormat decimalFormat = new DecimalFormat("#,##0.#####");
String formattedDouble = decimalFormat.format(someDouble);
This allows you to easily convert double values to strings that look like this:
1,234,567.89012
If you need more precision or numbers larger than what Long.MAX_VALUE can handle, you should checkout java's BigDecimal class.
BigDecimal provides it's own round method that allows you to specify what to round to. You can still use the DecimalFormat class by calling BigDecimal's doubleValue() function.

multiplying DecimalFormat number (no longer rounded properly)

I'm basically trying to use DecimalFormat to get to two decimal places. I'm taking two integer values then dividing them and casting to a double I've put in sample values below. When I do as below I get a value that is no longer to two decimal places. It seems to be when multiply by the 3 it loses it's rounding.
DecimalFormat df = new DecimalFormat("#.00");
double d = Double.parseDouble(df.format((double)5/6))*3;
System.out.println(d);
Can you let me know why this occurs and how to fix this?

In the statemet:
double d = Double.parseDouble(df.format((double)5/6))*3;
the formatting is not preserved (Double returns a double).
You could do, e.g.:
System.out.println(df.format(d));

Decimal Formatting is not working

I want to be able to make sure a number only has two decimal places.
E.G Area entered = 256.12345 so Area would be 256.12.
This is what I have:
DecimalFormat df = new DecimalFormat( "#,###,###,##0.00" );
double area = new Double(area.format(area)).doubleValue();
area = (double)(r*r);

You're not actually using the instance df.
Change your code to use it instead of calling methods on area (which won't work, since primitives don't have methods):
double area = new Double(df.format(area)).doubleValue();
However, the formality of precision is more for printing purposes than storing purposes (Double will store it in the IEEE floating point standard for doubles, which may lead to imprecise floating point values).
To get around that, use a BigDecimal instead, with a precision of 2:
BigDecimal decimal = new BigDecimal(area);
decimal.setScale(2);
System.out.println(decimal); // will print area to two decimal places

This is the way you do it.
//formatting numbers upto 2 decimal places in Java
DecimalFormat df = new DecimalFormat("#,###,##0.00");
System.out.println(df.format(364565.14));
System.out.println(df.format(364565.1454));
//formatting numbers upto 3 decimal places in Java
df = new DecimalFormat("#,###,##0.000");
System.out.println(df.format(364565.14));
System.out.println(df.format(364565.1454));
}
}
Output:
364,565.14
364,565.15
364,565.140
364,565.145

Java, rounding a double to two decimal places

I'm trying to round a double to the nearest two decimal places however, it is just rounding to the nearest full number.
For example, 19634.0 instead of 19634.95.
This is the current code I use for the rounding
double area = Math.round(Math.PI*Radius()*Radius()*100)/100;
I can't see where i am going wrong.
Many thanks for any help.

Well, Math.round(Math.PI*Radius()*Radius()*100) is long. 100 is int.
So Math.round(Math.PI*Radius()*Radius()*100) / 100 will become long (19634).
Change it to Math.round(Math.PI*Radius()*Radius()*100) / 100.0. 100.0 is double, and the result will also be double (19634.95).

You can use a DecimalFormat object:
DecimalFormat df = new DecimalFormat ();
df.setMaximumFractionDigits (2);
df.setMinimumFractionDigits (2);
System.out.println (df.format (19634.95));

Do you actually want want to round the value to 2 places, which will cause snowballing rounding errors in your code, or simply display the number with 2 decimal places? Check out String.format(). Complex but very powerful.

You might want to take a look at the DecimalFormat class.
double x = 4.654;
DecimalFormat twoDigitFormat = new DecimalFormat("#.00");
System.out.println("x=" + twoDigitFormat.format());
This gives "x=4.65". The difference between # and 0 in the pattern is that the zeros are always displayed and # will not if the last ones are 0.

The following example came from this forum, but seems to be what you are looking for.
double roundTwoDecimals(double d) {
DecimalFormat twoDForm = new DecimalFormat("#.##");
return Double.valueOf(twoDForm.format(d));
}

Regarding rounding off a value to certain decimal point

I was going through the class decimal format as I was trying format a decimal number in Java upto 2 decimal places or 3 decimal places.
I come up with this solution as shown below but please also let me know are there any other alternative that java provides us to achieve the same thing..!!
import java.text.DecimalFormat;
public class DecimalFormatExample {
public static void main(String args[]) {
//formatting numbers upto 2 decimal places in Java
DecimalFormat df = new DecimalFormat("#,###,##0.00");
System.out.println(df.format(364565.14));
System.out.println(df.format(364565.1454));
//formatting numbers upto 3 decimal places in Java
df = new DecimalFormat("#,###,##0.000");
System.out.println(df.format(364565.14));
System.out.println(df.format(364565.1454));
}
}
Output:
364,565.14
364,565.15
364,565.140
364,565.145
Please advise what are other alternatives that java provide us to achieve the same thing..!!

If you are bothered by re-defining your DecimalFormat, or if you suspect you'll be needing to do redefine many times, you could also do inline formatting with String.format(). Check the syntax for Formatter especially the Numeric sub-title.

Here is an alternative to round off...
double a = 123.564;
double roundOff = Math.round(a * 10.0) / 10.0;
System.out.println(roundOff);
roundOff = Math.round(a * 100.0) / 100.0;
System.out.println(roundOff);
The output is
123.6
123.56
Number of 0s while multiplying and dividing decides the rounding off.

Here is one method.
float round(float value, int roundUpTo){
float x=(float) Math.pow(10,roundUpTo);
value = value*x; // here you will guard your decimal points from loosing
value = Math.round(value) ; //this returns nearest int value
return (float) value/p;
}