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

user_82474 0
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I have a double in Java and I want to check if it is NaN. What is the best way to do this?

nan double equality java
7 Answers

If your value under test is a Double (not a primitive) and might be null (which is obviously not a number too), then you should use the following term:

(value==null || Double.isNaN(value))

Since isNaN() wants a primitive (rather than boxing any primitive double to a Double), passing a null value (which can't be unboxed to a Double) will result in an exception instead of the expected false.

user_143403880

The below code snippet will help evaluate primitive type holding NaN.

double dbl = Double.NaN; Double.valueOf(dbl).isNaN() ? true : false;

user_17471380
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