Convert a String to Double - Java

Question

What is the easiest and correct way to convert a String number with commas (for example: 835,111.2) to a Double instance.

Thanks.

Answer 1

Have a look at java.text.NumberFormat. For example:

import java.text.*; import java.util.*;  public class Test {     // Just for the sake of a simple test program!     public static void main(String[] args) throws Exception     {         NumberFormat format = NumberFormat.getInstance(Locale.US);          Number number = format.parse("835,111.2");         System.out.println(number); // or use number.doubleValue()     } } 

Depending on what kind of quantity you're using though, you might want to parse to a BigDecimal instead. The easiest way of doing that is probably:

BigDecimal value = new BigDecimal(str.replace(",", "")); 

or use a DecimalFormat with setParseBigDecimal(true):

DecimalFormat format = (DecimalFormat) NumberFormat.getInstance(Locale.US); format.setParseBigDecimal(true); BigDecimal number = (BigDecimal) format.parse("835,111.2"); 

Answer 2

The easiest is not always the most correct. Here's the easiest:

String s = "835,111.2"; // NumberFormatException possible. Double d = Double.parseDouble(s.replaceAll(",","")); 

I haven't bothered with locales since you specifically stated you wanted commas replaced so I'm assuming you've already established yourself as a locale with comma is the thousands separator and the period is the decimal separator. There are better answers here if you want correct (in terms of internationalization) behavior.