How to convert a binary number to decimal in Python

How to convert a binary number to decimal in Python.

Here's a step-by-step tutorial on how to convert a binary number to decimal in Python:

First, let's understand the concept of binary and decimal numbers. Binary is a base-2 number system that uses only two digits, 0 and 1. On the other hand, decimal is a base-10 number system that uses digits from 0 to 9.
To convert a binary number to decimal, we need to multiply each digit of the binary number by the corresponding power of 2 and sum them up.
Let's start by taking the binary number as input from the user. You can use the input() function to prompt the user to enter a binary number. Here's an example:

binary = input("Enter a binary number: ")

Next, we'll define a variable decimal to store the decimal equivalent of the binary number. Initialize it with 0.

decimal = 0

Now, we'll iterate through each digit of the binary number from right to left. We can use a for loop for this. Here's an example:

for i in range(len(binary)):
    # code to be added later

Inside the loop, we'll check each digit of the binary number. If it is 1, we'll add the corresponding power of 2 to the decimal variable. We can use the pow() function to calculate the power of 2. Here's the updated code inside the loop:

for i in range(len(binary)):
    if binary[i] == '1':
        decimal += pow(2, len(binary) - 1 - i)

Finally, we'll print the decimal equivalent of the binary number. Here's the complete code:

binary = input("Enter a binary number: ")
decimal = 0

for i in range(len(binary)):
    if binary[i] == '1':
        decimal += pow(2, len(binary) - 1 - i)

print("Decimal equivalent:", decimal)

Let's test the code with an example. Suppose the user enters the binary number 10101. The code will calculate the decimal equivalent as 21 and print it. Output:

Enter a binary number: 10101
Decimal equivalent: 21

That's it! You've successfully converted a binary number to decimal in Python.