How to Convert String variables to double in Java Program

Java Program to convert string variables to double

Java Strings

  • A String object is an instance of the java.lang.String class, which is immutable and final. This means that once a String object is created, its value cannot be changed.
  • you can create new strings by concatenating existing strings or by creating a new string that is a substring of an existing string.
  • Strings in Java are immutable, which means that once you create a string object, its value cannot be changed.
  • You must be familiar with following topics to understand the correspond example Such as: Java Strings, Java Data Types. 

Steps to convert string variables to double 

  • Here are the steps to convert string variables to double  in Java:, You can follow these steps:
    • Store the string representation of a number in a String variable.

    • Use the Double.parseDouble() method to convert the string to a double. The method takes the string representation of a number as its argument and returns the equivalent double value.

    • Store the result of the Double.parseDouble() method in a double variable.

    • If the string passed to Double.parseDouble() cannot be successfully parsed into a double, a NumberFormatException will be thrown.

    • To handle this exception, you can wrap the call to Double.parseDouble() in a try-catch block.

Let’s look at a Java Program to convert string variables to double in Java to perform certain operations.

Example 1: Java Program to convert string variables to double

Run
public class Main {
  public static void main(String[] args) {
    String numberAsString = "1234.56";
    double numberAsDouble = Double.parseDouble(numberAsString);
    System.out.println("The number as a double: " + numberAsDouble);
  }
}

Output

The number as a double: 1234.56

Example 2 : Java Program to convert string variables to double

Run
public class Main {
  public static void main(String[] args) {
    String numberAsString = "7654.23";
    double numberAsDouble = 0.0;
    
    try {
      numberAsDouble = Double.parseDouble(numberAsString);
    } catch (NumberFormatException e) {
      System.out.println("Invalid number format.");
      return;
    }
    
    System.out.println("The number as a double: " + numberAsDouble);
  }
}

Output

The number as a double: 7654.23

Example 3: Java Program to convert string variables to double

Run
public class Main{
   public static void main(String args[]){
	String str = "809.989";

	/* Convert String to double using 
	 * parseDouble(String) method of Double
	 * wrapper class
	 */
	double dnum = Double.parseDouble(str);
		
	//displaying the value of variable dnum
	System.out.println(dnum);
   }
}

Output

809.989

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