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 decimal places? For example, I have these values: ``` double d1 = 123456.78; double d2 = 567890; ``` And I want to print them in the following way, for example with US locale and 2 decimal places: ``` 123,456.78 567,890.00 ``` I don't actually care about rounding mode in this case, because these double values are gained from a `BigDecimal` with the given scale, so their number of decimal places is always lesser or equal than the number of decimal places I want to print. Edit: To make things a bit more clear, the thing is that I want to display money in a locale dependent way, but with a fixed number of decimal places. The example above showed, how the values should be formatted if the system locale is `en_US`. Now lets say, the system locale is `cs_CZ` (Czech), so the same numbers should be formatted in this way: ``` 123 456,78 567 890,00 ``` Now, how c…

Accepted Answer

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).

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

Solution

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