Java - Double isNaN(double) method

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Description

The Java Double isNaN(double v) method returns true if the specified number is a Not-a-Number (NaN) value, false otherwise.The argument v is the value to be tested.

Declaration

Following is the declaration for java.lang.Double.isNan(double) method

public static boolean isNaN(double v)

Parameters

v − This is the value to be tested.

Return Value

This method returns true if the value of the argument is NaN; false otherwise.

Exception

NA

Checking double to be NAN Example

The following example shows the usage of Double isNaN() method to check if a Double object carries a NaN value. We've initialized a double value with an expression which result in positive infinity. Then using isNaN() method, we're checking its value.

package com.tutorialspoint;
public class DoubleDemo {
   public static void main(String[] args) {
      double d = 1.0/0.0;
   
      // returns true if NaN
      System.out.println(d + " = " + Double.isNaN(d));
   }
} 

Output

Let us compile and run the above program, this will produce the following result −

Infinity = false

Checking double to be NAN Example

The following example shows the usage of Double isNaN() method to check if a Double object carries a NaN value. We've initialized a double value with an expression which result in negative infinity. Then using isNaN() method, we're checking its value.

package com.tutorialspoint;
public class DoubleDemo {
   public static void main(String[] args) {
      double d = -1.0/0.0;
   
      // returns true if NaN
      System.out.println(d + " = " + Double.isNaN(d));
   }
} 

Output

Let us compile and run the above program, this will produce the following result −

-Infinity = false

Checking double to be NAN Example

The following example shows the usage of Double isNaN() method to check if a Double object carries a NaN value. We've initialized a double value with an expression which result in NAN. Then using isNaN() method, we're checking its value.

package com.tutorialspoint;
public class DoubleDemo {
   public static void main(String[] args) {
      double d = 0.0/0.0;
   
      // returns true if NaN
      System.out.println(d + " = " + Double.isNaN(d));
   }
} 

Output

Let us compile and run the above program, this will produce the following result −

NaN = true

Checking double to be NAN Example

The following example shows the usage of Double isNaN() method to check if a Double object carries a NaN value. We've initialized a double value with an expression which result in zero value. Then using isNaN() method, we're checking its value.

package com.tutorialspoint;
public class DoubleDemo {
   public static void main(String[] args) {
      double d = 0.0/1.0;
   
      // returns true if NaN
      System.out.println(d + " = " + Double.isNaN(d));
   }
} 

Output

Let us compile and run the above program, this will produce the following result −

0.0 = false