How to format a Double coming from a Object in Java?

Question

I want to format a Double obtained from an Object so it only displays three digits after the decimal point. Here's the current code:

 Three a = Data.get(index); 
 // Get the y-axis acceleration value
 double b = a.getY();
 String accelerationOutUnfiltered = Double.toString(b);
 Data[0] = accelerationOutUnfiltered;

Note: I am doing this in Android, and when I use String.format("%.3f", y) this doesn't work and it throws me a error in Android Studio. Currently the above code works but it displays 15 digits after the decimal point.

I have tried several forms, but they all have failed. Please help. Thanks :)

you should use decimalFormat class as inn the answer below... can we see the code you try???? — ΦXocę 웃 Пepeúpa ツ, Jul 16 '16 at 16:49
Also refer http://stackoverflow.com/questions/153724/how-to-round-a-number-to-n-decimal-places-in-java — Unknown, Jul 16 '16 at 16:49
What is the error you're getting from String.format("%.3f", y) — Kariem, Jul 16 '16 at 16:52

score 1 · Answer 1 · answered Jul 16 '16 at 16:46

1

You could use DecimalFormatter.

For example:

double b = a.getY();

DecimalFormat formatter = new DecimalFormat("#.###");
formatter.setRoundingMode(RoundingMode.CEILING);

String formattedDouble = formatter.format(b);

answered Jul 16 '16 at 16:46

earthw0rmjim

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That worked. Thank you. Now, I need to do it for formatting three values to write them in a file. I tried: String a= formatter2.format(g, h, i); But it doesn't work. – jlopez Jul 16 '16 at 17:45
Format the values separately, and then concatenate them into one `String`. – earthw0rmjim Jul 16 '16 at 17:51

score 0 · Answer 2 · answered Jul 16 '16 at 16:47

0

Have tried decimal formatter?

You do something like this:

DecimalFormat df = new DecimalFormat("#.#####");
df.format(<your_number>);

answered Jul 16 '16 at 16:47

akortex

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How to format a Double coming from a Object in Java?

2 Answers2