How to convert a double to long without casting?

java type-conversion
rich picture rich · Nov 26, 2008 · Viewed 334.5k times · Source

What is the best way to convert a double to a long without casting?

For example:

double d = 394.000;
long l = (new Double(d)).longValue();
System.out.println("double=" + d + ", long=" + l);

Answer

Jon Skeet picture Jon Skeet · Nov 26, 2008

Assuming you're happy with truncating towards zero, just cast:

double d = 1234.56;
long x = (long) d; // x = 1234

This will be faster than going via the wrapper classes - and more importantly, it's more readable. Now, if you need rounding other than "always towards zero" you'll need slightly more complicated code.

Related questions

How do I convert a String to an int in Java?

How can I convert a String to an int in Java? My String contains only numbers, and I want to return the number it represents. For example, given the string "1234" the result should be the number 1234.

Read More
How do I convert from int to String?

I'm working on a project where all conversions from int to String are done like this: int i = 5; String strI = "" + i; I'm not familiar with Java. Is this usual practice or is something wrong, as I suppose?

Read More
Create ArrayList from array

I have an array that is initialized like: Element[] array = {new Element(1), new Element(2), new Element(3)}; I would like to convert this array into an object of the ArrayList class. ArrayList<Element> arraylist = ???;

Read More