Here you can find the source of doubleToScientificString(double number, int fractionDigits)
| Parameter | Description |
|---|---|
| number | the double to convert |
| fractionDigits | the number of digits in the fraction part, e.g., 4 in "1.2345e+05". |
public static String doubleToScientificString(double number, int fractionDigits)
//package com.java2s; /*/* ww w . ja va 2 s.c o m*/ * Copyright 1999-2002 Carnegie Mellon University. * Portions Copyright 2002 Sun Microsystems, Inc. * Portions Copyright 2002 Mitsubishi Electric Research Laboratories. * All Rights Reserved. Use is subject to license terms. * * See the file "license.terms" for information on usage and * redistribution of this file, and for a DISCLAIMER OF ALL * WARRANTIES. * */ import java.text.DecimalFormat; public class Main { /** * Returns the string representation of the given double value in normalized scientific notation. The * <code>fractionDigits</code> argument gives the number of decimal digits in the fraction portion. For example, if * <code>fractionDigits</code> is 4, then the 123450 will be "1.2345e+05". There will always be two digits in the * exponent portion, and a plus or minus sign before the exponent. * * @param number the double to convert * @param fractionDigits the number of digits in the fraction part, e.g., 4 in "1.2345e+05". * @return the string representation of the double in scientific notation */ public static String doubleToScientificString(double number, int fractionDigits) { DecimalFormat format = new DecimalFormat(); StringBuilder formatter = new StringBuilder(5 + fractionDigits) .append("0."); for (int i = 0; i < fractionDigits; i++) { formatter.append('0'); } formatter.append("E00"); format.applyPattern(formatter.toString()); String formatted = format.format(number); int index = formatted.indexOf('E'); if (formatted.charAt(index + 1) != '-') { return formatted.substring(0, index + 1) + '+' + formatted.substring(index + 1); } else { return formatted; } } }