How to mark empty in a single element in a float array

Question

I have a large float (primitive) array and not every element in the array is filled. How can i mark a particular element as EMPTY. I understand this can be achieved by some special symbols but still i would like to know the standard way. Even if i am using some special symbol , how will i handle a situation where the actual data item is the value of special symbol. In short my question is how to implement the NULL feature in a primitive type array in java.

PS - The reason why i am not using Float object is to achieve a high memory and speed performance.

Thanks Vineeth

Answer 1

You could use Float.NaN, no valid value will ever be that.

Note that one NaN is never equal to another NaN, so you can check if something is NaN by:

float a = Float.NaN;
if( a != a ) {
    System.out.println("wat?");
}

In code intended for people to read, you should use Float.isNaN method though.

Answer 2

Can you use Float.NaN?

public class FloatArray {
    public static void main(String[] args) {
        float[] data = new float[10];
        data[5] = Float.NaN;
        for (float f : data){
            if (Float.isNaN(f)){
                System.out.println("No Valve");
            } else {
                System.out.println(f);
            }
        }
    }
}

Then where is not risk of using a Sentianl Value like -1 that may be valid and you can test using Float#isNaN(f)