Formatting a double and not rounding off

Question

I need to format (and not round off) a double to 2 decimal places.

I tried with:

String s1 = "10.126";
Double f1 = Double.parseDouble(s1);
DecimalFormat df = new DecimalFormat(".00");
System.out.println("f1"+df.format(f1));

Result:

10.13

But I require the output to be 10.12

This was asked the same week here https://stackoverflow.com/questions/8486878/how-to-cut-off-decimal-in-java-without-rounding -- this has lot more options — Asif Mohammed, Feb 17 '17 at 23:03

Bohemian · Answer 1 · 2011-12-19T11:40:19.497

25

Call setRoundingMode to set the RoundingMode appropriately:

String s1 = "10.126";
Double f1 = Double.parseDouble(s1);
DecimalFormat df = new DecimalFormat(".00");
df.setRoundingMode(RoundingMode.DOWN); // Note this extra step
System.out.println(df.format(f1));

Output

10.12

edited Dec 19 '11 at 11:40

answered Dec 19 '11 at 11:35

Bohemian

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Thanks for the suggestion..but i need to use java 1.5 ..i guess the setRoundingMode() is available in 1.6 – SMA_JAVA Dec 19 '11 at 11:54
See my answer using BigDecimal instead – Brad Dec 19 '11 at 16:55
Yes, I am using the current version - 1.6. It would behoove you to upgrade your version too. – Bohemian Dec 19 '11 at 21:58

score 11 · Answer 2 · answered Dec 19 '11 at 11:33

11

You can set the rounding mode of the formatter to DOWN:

df.setRoundingMode(RoundingMode.DOWN);

answered Dec 19 '11 at 11:33

MByD

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score 3 · Answer 3 · answered Dec 19 '11 at 14:35

3

Why not use BigDecimal

BigDecimal a = new BigDecimal("10.126");
BigDecimal floored = a.setScale(2, BigDecimal.ROUND_DOWN);  //  == 10.12

answered Dec 19 '11 at 14:35

Brad

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score 0 · Answer 4 · answered Dec 19 '11 at 11:32

0

Have you tried RoundingMode.FLOOR?

String s1 = "10.126";
Double f1 = Double.parseDouble(s1);
DecimalFormat df = new DecimalFormat(".00");
df.setRoundingMode(RoundingMode.FLOOR);

System.out.println("f1"+df.format(f1));

answered Dec 19 '11 at 11:32

John B

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You mean Math.round(arg0); ?? Actually that would round it off to the closest integer. – SMA_JAVA Dec 19 '11 at 11:34
No DecimalFormat's setRoundingMode – John B Dec 19 '11 at 11:36

score 0 · Answer 5 · answered Dec 19 '11 at 11:49

0

If all you want to do is truncate a string at two decimal places, consider using just String functions as shown below:

String s1 = "10.1234";
String formatted = s1;
int numDecimalPlaces = 2;
int i = s1.indexOf('.');
if (i != -1 && s1.length() > i + numDecimalPlaces) {
    formatted = s1.substring(0, i + numDecimalPlaces + 1);
}
System.out.println("f1" + formatted);

This saves on parsing into a Double and then formatting back into a String.

answered Dec 19 '11 at 11:49

dogbane

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Thanks man....i can use it ...but then i wanted something more compact..and also i need to do a couple of calculations on these values, so any ways there will be some amount of parsing required – SMA_JAVA Dec 19 '11 at 12:01

Formatting a double and not rounding off

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