Detailed usage of DecimalFormat in Java, javadecimalformat

Detailed usage of DecimalFormat in Java, javadecimalformat

We often need to format numbers, such as taking 2 decimal places, which is the most common. Java provides the DecimalFormat class to help you format numbers as quickly as possible. The following is an example:

Importjava. text. decimalFormat; public class TestNumberFormat {public static void main (String [] args) {doublepi = 3.1415927; // The circumference rate // gets an integer System. out. println (newDecimalFormat ("0 "). format (pi); // 3 // take an integer and two decimal places System. out. println (newDecimalFormat ("0.00 "). format (pi); // 3.14 // take two integers and three decimal places. The less integer is filled with 0. System. out. println (new DecimalFormat ("00.000 "). format (pi); // 03.142 // obtain all integer parts of the System. out. println (newDecimalFormat ("#"). format (pi); // 3 // count by percentage, and take two decimal places System. out. println (new DecimalFormat ("#. # % "). format (pi); // 314.16% longc = 299792458; // speed of light // display as scientific notation, and take the five decimal places System. out. println (newDecimalFormat ("#. ##### E0 "). format (c); // 2.99792E8 // displays the scientific notation of two integers, and takes four decimal places. out. println (newDecimalFormat ("00. #### E0 "). format (c); // 29.9792E7 // each three digits are separated by commas. System. out. println (newDecimalFormat (",###"). format (c); // 299,792,458 // embed the format into the text System. out. println (newDecimalFormat ("the speed of light is every second, ### meters. "). Format (c ));}}

The DecimalFormat class mainly uses the # And 0 placeholder numbers to specify the number length. 0 indicates that if the number of digits is insufficient, it is filled with 0. # indicates that the number is pulled to this position whenever possible. The above example contains almost all the basic usage. For more information, see the documentation of the DecimalFormat class.

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