Is it good practice to use the xor operator for boolean checks? [closed]

Answer 1

If the usage pattern justifies it, why not? While your team doesn't recognize the operator right away, with time they could. Humans learn new words all the time. Why not in programming?

The only caution I might state is that "^" doesn't have the short circuit semantics of your second boolean check. If you really need the short circuit semantics, then a static util method works too.

public static boolean xor(boolean a, boolean b) {
    return (a && !b) || (b && !a);
}

Answer 2

You could always just wrap it in a function to give it a verbose name:

public static boolean XOR(boolean A, boolean B) {
    return A ^ B;
}

But, it seems to me that it wouldn't be hard for anyone who didn't know what the ^ operator is for to Google it really quick. It's not going to be hard to remember after the first time. Since you asked for other uses, its common to use the XOR for bit masking.

You can also use XOR to swap the values in two variables without using a third temporary variable.

// Swap the values in A and B
A ^= B;
B ^= A;
A ^= B;

Here's a Stackoverflow question related to XOR swapping.

Answer 3

With code clarity in mind, my opinion is that using XOR in boolean checks is not typical usage for the XOR bitwise operator. From my experience, bitwise XOR in Java is typically used to implement a mask flag toggle behavior:

flags = flags ^ MASK;

This article by Vipan Singla explains the usage case more in detail.

If you need to use bitwise XOR as in your example, comment why you use it, since it's likely to require even a bitwise literate audience to stop in their tracks to understand why you are using it.

Answer 4

str.contains("!=") ^ str.startsWith("not(")

looks better for me than

str.contains("!=") != str.startsWith("not(")

Answer 5

I find that I have similar conversations a lot. On the one hand, you have a compact, efficient method of achieving your goal. On the other hand, you have something that the rest of your team might not understand, making it hard to maintain in the future.

My general rule is to ask if the technique being used is something that it is reasonable to expect programmers in general to know. In this case, I think that it is reasonable to expect programmers to know how to use boolean operators, so using xor in an if statement is okay.

As an example of something that wouldn't be okay, take the trick of using xor to swap two variables without using a temporary variable. That is a trick that I wouldn't expect everybody to be familiar with, so it wouldn't pass code review.

Answer 6

You can simply use != instead.