Round a double to 4 decimals or less

Question

I'm currently using the method :

String.format("%.4", myDouble);

The trouble with this is that if I get a number with less decimals, such as 2.34, it will display 2.3400 . Is there a way to avoid that ?

If you are talking about a percentage or using this in a scientific context, it might be clearer to write them all with the same number of decimals. For example, if it's exactly 2.3400% and the next number is 5.8794%, then the former should be written as 2.3400. Here, the zeroes are significant. — rajah9, Oct 26 '15 at 15:58
http://stackoverflow.com/questions/11701399/round-up-to-2-decimal-places-in-java — Reimeus, Oct 26 '15 at 16:01

Gaël J · Answer 1 · 2015-10-26T16:08:53.027

4

Using DecimalFormat and pattern #.#### should work. It will display up to 4 digits after the decimal point but it might be less if no need.

See http://docs.oracle.com/javase/tutorial/i18n/format/decimalFormat.html

edited Oct 26 '15 at 16:08

answered Oct 26 '15 at 15:59

Gaël J

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score 2 · Answer 2 · answered Oct 26 '15 at 15:56

2

You can use Math.round function :) example:

Math.round(192.15515452*10000)/10000.0

returns 192.1551

and Math.round(192.15*10000)/10000.0

returns 192.15

answered Oct 26 '15 at 15:56

Shivam

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score 1 · Accepted Answer · answered Oct 26 '15 at 16:27

Use DecimalFormat and a pattern.

double value = 2.34;
String pattern = "#.####";
DecimalFormat myFormatter = new DecimalFormat(pattern);
String output = myFormatter.format(value);

System.out.println(value + " " + pattern + " " + output);  // displays  2.34 #.#### 2.34

For more references Customizing Formats

Round a double to 4 decimals or less

3 Answers3