Java: Format number in millions

Question

Is there a way to use DecimalFormat (or some other standard formatter) to format numbers like this:

1,000,000 => 1.00M

1,234,567 =>

Answer 1

Note that if you have a BigDecimal, you can use the movePointLeft method:

new DecimalFormat("#.00").format(value.movePointLeft(6));

Answer 2

Here's a subclass of NumberFormat that I whipped up. It looks like it does the job but I'm not entirely sure it's the best way:

private static final NumberFormat MILLIONS = new NumberFormat()
{
    private NumberFormat LOCAL_REAL = new DecimalFormat("#,##0.00M");

    public StringBuffer format(double number, StringBuffer toAppendTo, FieldPosition pos)
    {
        double millions = number / 1000000D;
        if(millions > 0.1) LOCAL_REAL.format(millions, toAppendTo, pos);

        return toAppendTo;
    }

    public StringBuffer format(long number, StringBuffer toAppendTo, FieldPosition pos)
    {
        return format((double) number, toAppendTo, pos);
    }

    public Number parse(String source, ParsePosition parsePosition)
    {
        throw new UnsupportedOperationException("Not implemented...");
    }
};

Answer 3

String.format("%.2fM", theNumber/ 1000000.0);

For more information see the String.format javadocs.

Answer 4

Why not simply?

DecimalFormat df = new DecimalFormat("0.00M");
System.out.println(df.format(n / 1000000));

Answer 5

In Kotlin language, you can make extention function:

fun Long.formatToShortNumber(): String {
    return when {
        this >= 1000000000 -> String.format("%.2fB", this / 1000000000.0)
        this >= 1000000 -> String.format("%.2fM", this / 1000000.0)
        this >= 1000 -> String.format("%.2fK", this / 1000.0)
        else -> this.toString()
    }
}

Answer 6

Take a look at ChoiseFormat.

A more simplistic way would be to use a wrapper that auto divided by 1m for you.