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I have two object arrays like so:
Object[] array1 = {0, 1, 2, 3};
Object[] array2 = {0, 1, 2, 3};
I would like to know if the arrays are equal. I'm defining equal as every value in array1 is the same as the value in that position in the array2. So these two arrays would be equal.
What is the best why to find out if these two arrays are equal?
if(array1 == array2)
is not a deep equals so that won't work and I don't know if looping over each element and comparing them is the best and most efficient way to solve this problem. Does anyone have any better suggestions?
Edit: I needed an equals that can go into nested arrays.
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Java provides a direct method Arrays. equals() to compare two arrays. Actually, there is a list of equals() methods in the Arrays class for different primitive types (int, char, ..etc) and one for Object type (which is the base of all classes in Java).
So far we only compared arrays based on their object identities. On the other hand, to check if two arrays are equal in terms of their contents, Java provides the Arrays. equals static method. This method will iterate through the arrays, per position in parallel, and apply the == operator, for every pair of elements.
The equals() method of java. util. Set class is used to verify the equality of an Object with a Set and compare them. The method returns true if the size of both the sets are equal and both contain the same elements.
Using Arrays. equals(array1, array2) methods − This method iterates over each value of an array and compare using equals method. Using Arrays. deepEquals(array1, array2) methods − This method iterates over each value of an array and deep compare using any overridden equals method.
In Java, the == operator compares that two references are identical or not. Whereas the equals() method compares two objects. Objects are equal when they have the same state (usually comparing variables).
Use Arrays.deepEquals(). This does the same job as Arrays.equals() but also works with nested arrays.
Returns true if the two specified arrays are deeply equal to one another. Unlike the
equals(Object[],Object[])method, this method is appropriate for use with nested arrays of arbitrary depth.Two array references are considered deeply equal if both are null, or if they refer to arrays that contain the same number of elements and all corresponding pairs of elements in the two arrays are deeply equal.
Two possibly null elements e1 and e2 are deeply equal if any of the following conditions hold:
- e1 and e2 are both arrays of object reference types, and Arrays.deepEquals(e1, e2) would return true
- e1 and e2 are arrays of the same primitive type, and the appropriate overloading of Arrays.equals(e1, e2) would return true.
- e1 == e2
- e1.equals(e2) would return true.
Note that this definition permits null elements at any depth.
If either of the specified arrays contain themselves as elements either directly or indirectly through one or more levels of arrays, the behavior of this method is undefined.
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