Still Struggling to use XOR in Python? If yes, then check out the best uses of XOR operation in Python along with how to use it effectively.
Operators are keywords in python that are the essential building blocks of any program instruction. Operators can be Arithmetic(related to mathematical operations), Logical (help to implement logic) or as in our case Bitwise(those who work on the binary numbers).
Without operators, no practical program can be written. This article talks about one important Bitwise operator, the XOR operator.
What is XOR operator?
The XOR operator, also called the exclusive OR operator, is a highly useful bitwise operator in python.
The Bitwise operators or the Binary operators are operators that don’t work on the binary level. These operators perform specific operations for every bit of the operands, hence the name bitwise.
So what does the XOR operator do ? It reads every single bit from both operands and returns 0 if they are same, and 1 is they are different. The truth table for various cases of operands is given below.
| A | B | Result(A |
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
In python, the XOR operator is denoted by the ‘^’ symbol e.g., 1 ^ 0 = 1
Example
Let us understand the working of the XOR operator in detail by using an example
Let us say we have two numbers A = 10 and B = 11 and we perform the XOR operation on them
The Binary for A is 1010
The Binary of B is 1100
Now the result C = A ^ B can be calculated according to the following table
| A | B | C (A ^ B) |
| 1 | 1 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 0 | 0 | 0 |
| = 10 | = 11 | = 6 |
The answer is C = 0101 = 6
Basically we pick one bit from each operand, perform the XOR operation and repeat this process for every significant bit of both operands. What are significant bits, these are the bits that contain significant information.
Usage of XOR in Python
Let us implement the above example in python to see how it is implemented in code.
Example
# program to implement XOR in python
A = 0b1010
B = 0b1100
print(bin(A^B))
print(A^B)
Output
0b0110
6
Important Insight About XOR Operator
There is one interesting detail about the XOR operator that is used in various practical day-to-day applications. This makes XOR operator a very important and useful operator which any programmer should know.
“ If the result of XOR operation of two operands is again used to implement XOR operation with anyone of its initial operands, it gives the second operand .”
Example
A = 10
B = 11
C = A ^ B
print(f“A ^ B = {C}”)
print(f”the value of A is : {B^C}”)
print(f”the value of B is : {A^C}”)
Output
6
10
11
This does not seem like a big detail at first, but is used in many of the practical applications as discussed later in the article.
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Applications of XOR Operator
1. Swapping two variables without using a third variable
Swapping two variables is one of the basic and frequently done tasks in programming. While you may have seen swapping two variables using a third temporary variable, but using the XOR operator, we can do it we can do it without any other variable.
This is possible due to the property of XOR operation to return its operands, which is mentioned earlier in the article.
Let us take an example
Suppose we have two variables A = 5 and B = 6 and we want to swap them using XOR operation in python
The first step would be to find the XOR of A and B and storing it in one of the operands
A = A ^ B
So the value of A ^ B can be calculated as
101 ^ 110 = 011 = 3
So the value of A is currently 3. The next step is to set B = A ^ B
This seems counterintuitive at first, but A now contains the value of 5 ^ 6, which applied in XOR operation with B(6) will give the other operand(in this case 5) and store it in B
B = A ^ B
Now B contains the value which was initially in A. Now, if we XOR A(which currently contains 101 ^ 110 or 5 ^ 6) with B(which is having 5 or 101) we will get the value 6(which was initially in B) and store it in A
A = A ^ B
The final code looks something like this
Example
# Program to swap two variables using XOR
A = 5
B = 6
print(“Before swapping : ”)
print(f“A = {A}”)
print(f“B = {B}”)
A = A ^ B
B = A ^ B
A = A ^ B
print(“After Swapping : ”)
print(f“A = {A}”)
print(f“B = {B}”)
Output
Before swapping :
A = 5
B = 6
After swapping
A = 6
B = 5
2. Encryption
Encryption is the process of converting the data into a code format using a specific algorithm and a private key so that the data remains secure.
Data is a very important and private resource. Its theft can lead to many serious problems and may breach the users’ privacy. Hence it is important to protect the data by encrypting it.
In this way, even data gets stolen, the actual information cannot be decoded from the encrypted code without the private key. Hence the data remains secure.
Encrypting data through XOR operations was one of the first encryption techniques used. It is a bit outdated but still an important technique to learn.
Let us understand encryption using XOR in python using an example
Let the data be 47 which in binary is 101111 and we encrypt it using the key 9 which is 1001 in binary. So the data can be encrypted as
101111 ^ 001001 = 100110
The data that will be stored is 100110 which is 54 in binary. Now to decrypt it, we again XOR it with the key to get the original data
100110 ^ 001001 = 101111
The code for this encryption will look something like this
Example
# program to show encryption using XOR operation
data = 47
key = 9
enc_data = data ^ key
print(f“The encrypted data is : {enc_data}”)
print(f“The decrypted data is : {enc_data ^ key}”)
Output
The encrypted data is : 54
The decrypted data is : 47
3. Checking Equality
The XOR operator returns 0 for the same bits and 1 for different bits. This fact can be used to check equality of two variables.
If the XOR of two variables is 0 then they are equal, otherwise they are unequal
Conclusion
This is all about XOR in Python and its usage. The XOR operator is a bitwise operator which works on individual bits. It return 0 if the two operands are same and 1 if they are different.
It is used for many practical applications such as checking equality of variables, swapping two variables, encryption of data etc. If you believe that we have missed any critical part of XOR in Python then comment down below. If you like this information then please share this article with your friends.