Convert String to double in Java

Question

How can I convert a String such as \"12.34\" to a double in Java?

Answer 1

Use new BigDecimal(string). This will guarantee proper calculation later.

As a rule of thumb - always use BigDecimal for sensitive calculations like money.

Example:

String doubleAsString = "23.23";
BigDecimal price = new BigDecimal(doubleAsString);
BigDecimal total = price.plus(anotherPrice);

Answer 2

double d = Double.parseDouble(aString);

This should convert the string aString into the double d.

Answer 3

Using Double.parseDouble() without surrounding try/catch block can cause potential NumberFormatException had the input double string not conforming to a valid format.

Guava offers a utility method for this which returns null in case your String can't be parsed.

https://google.github.io/guava/releases/19.0/api/docs/com/google/common/primitives/Doubles.html#tryParse(java.lang.String)

Double valueDouble = Doubles.tryParse(aPotentiallyCorruptedDoubleString);

In runtime, a malformed String input yields null assigned to valueDouble

Answer 4

This is what I would do

    public static double convertToDouble(String temp){
       String a = temp;
       //replace all commas if present with no comma
       String s = a.replaceAll(",","").trim(); 
      // if there are any empty spaces also take it out.          
      String f = s.replaceAll(" ", ""); 
      //now convert the string to double
      double result = Double.parseDouble(f); 
    return result; // return the result
}

For example you input the String "4 55,63. 0 " the output will the double number 45563.0

Answer 5

String s = "12.34";
double num = Double.valueOf(s);

Answer 6

You only need to parse String values using Double

String someValue= "52.23";
Double doubleVal = Double.parseDouble(someValue);
System.out.println(doubleVal);