Formatting and Parsing Numbers - Java Language Basics

Java examples for Language Basics:Number Parse

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Description

Formatting and Parsing Numbers

Demo Code

import java.text.DecimalFormat;
import java.text.ParsePosition;

public class Main {
  private static DecimalFormat formatter = new DecimalFormat();
  public static void main (String[] args){
    formatNumber("##.##", 12.456);
    formatNumber("##.##", 12.456);
    formatNumber("0000.0000", 123.456);
    formatNumber("#.##", -123.456);

    // Positive and negative number format
    formatNumber("#.##;(#.##)", -123.345); 

    // Parse a string to decimal number
    String str = "XY4,123.123";
    String pattern = "#,###.###";
    formatter.applyPattern(pattern);/*from w w  w  .  j a v a2 s.c om*/

    // Create a ParsePosition object to specify the first digit of 
    // number in string. It is 4 in "XY4,123.983" and its index is 2.
    ParsePosition pp = new ParsePosition(2);

    Number numberObject = formatter.parse(str, pp);

    double value = numberObject.doubleValue();
    System.out.println("Parsed Value is " + value);
  }

  public static void formatNumber(String pattern, double value) {
      // Apply the pattern
      formatter.applyPattern ( pattern );

      // Format the number
      String formattedNumber = formatter.format(value) ;

      System.out.println("Number:" + value + ", Pattern:" + pattern +
                         ", Formatted Number:" + formattedNumber);
  }
}

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