Java:如何测试数组相等性? [英] Java: How to test on array equality?

问题描述

为什么下面的代码打印"Different."?

Why is the following code printing "Different."?

boolean[][] a = { {false,true}, {true,false} };
boolean[][] b = { {false,true}, {true,false} };

if (Arrays.equals(a, b) || a == b)
    System.out.println("Equal.");
else
    System.out.println("Different.");

推荐答案

为什么下面的代码打印Different."?

因为 Arrays.equals 执行浅比较.由于数组从 Object 继承了它们的 equals 方法，因此将对内部数组执行身份比较，这将失败，因为 a 和 b 不引用 same 数组.

Because Arrays.equals performs a shallow comparison. Since arrays inherit their equals-method from Object, an identity comparison will be performed for the inner arrays, which will fail, since a and b do not refer to the same arrays.

如果更改为 Arrays.deepEquals 它将按预期打印 "Equal.".

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