Question

How to compare two float arrays in Java

Answer 1

import java.util.Arrays;

class Main {
    public static void main(String[] args) {
        float[] floatArr1 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
        float[] floatArr2 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
    
        boolean equal = Arrays.equals(floatArr1, floatArr2);
        
        System.out.println(equal);
    }
}

   
/*
run:
 
true
 
*/

 

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Answer 2

/**
The epsilon exists because floating‑point numbers in Java (and in every mainstream 
language) are inherently imprecise. Even simple arithmetic produces tiny rounding errors, 
so comparing floats with == sometimes gives false mismatches
 
Two floats that should be equal often differ by a tiny amount,
so you treat them as “equal enough” if their difference is smaller than a tolerance.
*/
class Main {
    static boolean floatArraysEqual(float[] a, float[] b, float epsilon) {
        if (a.length != b.length) return false;
     
        for (int i = 0; i < a.length; i++) {
            // If the difference is larger than epsilon → treat as different
            // If the difference is smaller → treat as equal
            // You choose epsilon based on how much precision your application needs.
            if (Math.abs(a[i] - b[i]) > epsilon) {
                return false;
            }
        }
         
        return true;
    }
 
    public static void main(String[] args) {
        float[] floatArr1 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
        float[] floatArr2 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
     
        boolean equal = floatArraysEqual(floatArr1, floatArr2, 1e-6f);
         
        System.out.println(equal);
    }
}
 
    
/*
run:
  
true
  
*/

 

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Answer 3

class Main {
    static boolean floatArraysEqual(float[] a, float[] b) {
        if (a.length != b.length) return false;
     
        for (int i = 0; i < a.length; i++) {
            if (Float.compare(a[i], b[i]) != 0) {
                return false;
            }
        }
         
        return true;
    }
 
 
    public static void main(String[] args) {
        float[] floatArr1 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
        float[] floatArr2 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
     
        boolean equal = floatArraysEqual(floatArr1, floatArr2);
         
        System.out.println(equal);
    }
}
 
    
/*
run:
  
true
  
*/

 

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Answer 4

import java.util.stream.IntStream;

class Main {
    public static void main(String[] args) {
        float[] floatArr1 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
        float[] floatArr2 = new float[]{12314.9872f, 3.14f, 12387.88372f, 8878.57913f};
     
        boolean equal = 
            floatArr1.length == floatArr2.length &&
            IntStream.range(0, floatArr1.length)
                     .allMatch(i -> Math.abs(floatArr1[i] - floatArr2[i]) < 1e-6f);

  
         
        System.out.println(equal);
    }
}
 
    
/*
run:
  
true
  
*/

 

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