Java 12 introduced a new feature known as “Compact Number Formatting” that makes it easier to format numbers in a compact, readable way. This feature is especially useful when dealing with large numbers, such as those used in finance or scientific calculations.

In this blog article, we will explore what compact number formatting is, how it works, and how to use it in your Java applications.

What is Compact Number Formatting?

Compact Number Formatting is a new feature in Java 12 that allows you to format large numbers in a more compact and readable way. This feature is especially useful when dealing with numbers that are too large to be easily read by humans, such as those used in finance or scientific calculations.

The compact number formatting feature provides a way to format numbers in a way that is both concise and easy to read. It achieves this by using symbols to represent large numbers rather than writing out the entire number in digits. For example, instead of writing “1,000,000”, we can use the symbol “1M” to represent the same number.

How Compact Number Formatting Works

Compact Number Formatting works by mapping a numeric value to a compact representation using a set of rules. These rules are based on the current locale, which determines the symbols and formatting rules used for different number ranges.

The rules for compact number formatting are defined in the Unicode Common Locale Data Repository (CLDR) and are based on the language and region of the current locale. The CLDR defines a set of symbols for different number ranges, such as “K” for thousands, “M” for millions, and “B” for billions. It also defines the formatting rules for each range, such as the number of significant digits to display and whether to use scientific notation.

To format a number using compact number formatting, we use the `NumberFormat.getCompactNumberInstance()`

method to obtain a compact number formatter for the current locale. We can then use this formatter to format a number using the `format()`

method.

Example Usage

Let’s take a look at an example to see how compact number formatting works in practice. Suppose we have a large number, such as 1,234,567,890. We can format this number using compact number formatting as follows:

```
NumberFormat nf = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.SHORT);
String formatted = nf.format(1234567890);
System.out.println(formatted);
```

In this example, we obtain a compact number formatter for the US locale using the `NumberFormat.getCompactNumberInstance()`

method. We then use this formatter to format the number 1,234,567,890 using the `format()`

method, which returns the compact representation “1.2B”.

The `NumberFormat.Style.SHORT`

argument specifies that we want to use the shortest possible representation for the given number. There are also other styles available, such as `LONG`

and `NARROW`

, which provide different levels of detail and specificity.

Conclusion

Compact Number Formatting is a useful feature introduced in Java 12 that allows us to format large numbers in a more compact and readable way. This feature uses symbols to represent large numbers, which makes them easier to read and understand. By using the `NumberFormat.getCompactNumberInstance()`

method, we can obtain a compact number formatter for the current locale and use it to format large numbers in a concise and readable way.

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