How do you test to see if a double is equal to NaN?
Use the static Double.isNaN(double) method, or your Double's .isNaN() method.
// 1. static methodif (Double.isNaN(doubleValue)) { ...}// 2. object's methodif (doubleObject.isNaN()) { ...}Simply doing:
if (var == Double.NaN) { ...}is not sufficient due to how the IEEE standard for NaN and floating point numbers is defined.
Try Double.isNaN():
Returns true if this Double value is a Not-a-Number (NaN), false otherwise.
Note that [double.isNaN()] will not work, because unboxed doubles do not have methods associated with them.
You might want to consider also checking if a value is finite via Double.isFinite(value). Since Java 8 there is a new method in Double class where you can check at once if a value is not NaN and infinity.
/** * Returns {@code true} if the argument is a finite floating-point * value; returns {@code false} otherwise (for NaN and infinity * arguments). * * @param d the {@code double} value to be tested * @return {@code true} if the argument is a finite * floating-point value, {@code false} otherwise. * @since 1.8 */public static boolean isFinite(double d)