Compact Number Formatting – Localization
By Gigi Rosen / September 24, 2022 / No Comments / Compact Number Parsing, Conditional Formatting, Creating Resource Bundles, Formatting and Parsing Messages, Oracle Certifications, The ZonedDateTime Class
Compact Number Formatting
A compact number formatter creates a textual representation that represents the compact form of a number. This formatter is an instance of the CompactNumberFormat that can be created by calling the getCompactNumberInstance() factory method of the NumberFormat class. For example, the value 1_000_000 can be formatted in a compact form as “1M” or “1 million”.
The compact form can be specified by the constants of the enum type Number-Format.Style, shown in Table 18.6. The compact form has a suffix, depending on the value of the number and the locale. Suffixes for the US locale are shown in Table 18.6. The compact form of numbers below 1000 is without any suffix.
Table 18.6 Compact Number Styles
| Styles for compact number form | Verbosity | Suffix for the US locale in compact form |
| NumberFormat.Style.SHORT | Short number format style (default) | T (Trillion), B (Billion), M (Million), K (Thousand) Examples: 2T, 2.5M, 1.5K |
| NumberFormat.Style.LONG | Long number format style | trillion, billion, million, thousand Examples: 2 trillion, 2.5 million, 1.5 thousand |
The code below creates two compact number formatters for the US locale that use the SHORT and the LONG compact number styles, respectively, to format numbers to their compact form.
NumberFormat shortCompactFormat = NumberFormat.getCompactNumberInstance(
Locale.US, NumberFormat.Style.SHORT)
NumberFormat longCompactFormat = NumberFormat.getCompactNumberInstance(
Locale.US, NumberFormat.Style.LONG);
The compact number formatters are used on different numerical values to create their compact form, as shown in Table 18.7.
Table 18.7 Formatting Numbers to Compact Form
| Number n | Compact form returned by shortCompactFormatter.format(n) method | Compact form returned by longCompactFormatter.format(n) method |
| 9_400_000 9_500_000 12_500 12_510 999 | “9M” “10M” “12K” “13K” “999” | “9 million” “10 million” “12 thousand” “13 thousand” “999” |
9_400_000 9_500_000 12_500 12_510 999 | (Max fraction digits = 2) “9.4M” “9.5M” “12.5K” “12.51K” “999” | (Max fraction digits = 2) “9.4 million” “9.5 million” “12.5 thousand” “12.51 thousand” “999” |
System.out.println(shortCompactFormat.format(9_400_000)); // 9M
System.out.println(longCompactFormat.format(9_400_000)); // 9 million
The second row in Table 18.7 shows the compact form generated after the number of maximum fraction digits is set to 2 (p. 1122):
shortCompactFormat.setMaximumFractionDigits(2);
longCompactFormat.setMaximumFractionDigits(2);
Note the rounding that takes place depending on the value of the number. By default, RoundingMode.HALF_EVEN is used (see Table 18.9).