How to format double value for a given locale and number of decimal places?

Question

How can I use NumberFormat to format a double value for a given Locale (default locale is sufficient) and for a given number of decima

Answer 1

If you care to read NumberFormat's documentation, the solution would be obvious:

double d1 = 123456.78;
double d2 = 567890;
// self commenting issue, the code is easier to understand
Locale fmtLocale = Locale.getDefault(Category.FORMAT);
NumberFormat formatter = NumberFormat.getInstance(fmtLocale);
formatter.setMaximumFractionDigits(2);
formatter.setMinimumFractionDigits(2);
System.out.println(formatter.format(d1));
System.out.println(formatter.format(d2));
System.out.println(fmtLocale.toLanguageTag());

On my machine this prints out:

123 456,78
567 890,00
pl-PL

I believe this is what you are looking for, and you don't have to mess-up with patterns. I wouldn't do that - for instance there are locales which group digits by two, not by three (this is the reason we talk about grouping separator and not thousands separator).