round up this way (keeping up to decimal)

Question

How do i change 2.278481... to 2.2?

double a = 180;
double b = 79;
double x = (a/b);

Math.ceil() returns 3 and Math.floor() returns 2

@VatsalSura i want to keep 1 digit from floating. I can print it later — zorer, Jul 13 '16 at 09:58
If you only want 1 decimal place, multiply the value by 10, convert to an Int, then divide by 10 to a double. — Richard Goodman, Jul 13 '16 at 10:00

score 3 · Accepted Answer · answered Jul 13 '16 at 10:00

You can just set the setMaximumFractionDigits to 1. Like this:

public class Test {

public static void main(String[] args) {
    System.out.println(format(14.0184849945)); // prints '14.0'
    System.out.println(format(13)); // prints '13'
    System.out.println(format(3.5)); // prints '3.5'
    System.out.println(format(3.138136)); // prints '3.1'
}

 public static String format(Number n) {
    NumberFormat format = DecimalFormat.getInstance();
    format.setRoundingMode(RoundingMode.FLOOR);
    format.setMinimumFractionDigits(0);
    format.setMaximumFractionDigits(1);
    return format.format(n);
 }

}

This may helps you

score 0 · Answer 2 · answered Jul 13 '16 at 09:59

Try this:

public static String customFormat(String pattern, double value) {
    NumberFormat nf = NumberFormat.getNumberInstance(Locale.ENGLISH);
    DecimalFormat df = (DecimalFormat)nf;
    df.applyPattern(pattern);
    return df.format(value);

}

Calling:

double x = Double.parseDouble(customFormat("###.#", a/b);

This method does round up the numbers as well.

For the English locale:

, is not the decimal splitter. This is valid: ##,##,##,##.###

. is the decimal splitter. This is not valid: ##.##.##.##,### (at least not for this locale)

round up this way (keeping up to decimal)

2 Answers2