How do you test to see if a double is equal to NaN?

Question

I have a double in Java and I want to check if it is NaN. What is the best way to do this?

Answer 1

Try the static Double.isNaN(double) way, or your Double's .isNaN() method.

// 1. static method

if (Double.isNaN(doubleValue)) {

...

}

// 2. object's method

if (doubleObject.isNaN()) {

...

}

By Easily trying:

if (var == Double.NaN) {

...

}

is not sufficient due to how the IEEE standard for NaN and floating-point numbers are defined.