Notes

# List of characters that represent hexadecimal digits greater than 9 (A=10, B=11, ..., F=15)
hexx_list = ["A", "B", "C", "D", "E", "F"]

# Hexadecimal string that we want to convert to a decimal number
hexx = "AF"

# Initialize a variable to store the final decimal value
den = 0

# Loop through each character in the hexadecimal string `hexx`, starting from the right (least significant digit)
for i in range(len(hexx)):
# If the current character is a letter (i.e., A, B, C, D, E, F), we need to convert it to its decimal equivalent
if hexx[-1 - i] in hexx_list: # Access characters from right to left using negative indexing
# Find the index of the current character in `hexx_list` and add 10 to get its decimal equivalent
# A = 10, B = 11, ..., F = 15
hex_p = hexx_list.index(hexx[-1 - i]) + 10
print(hex_p) # Optional: print the decimal equivalent of the hexadecimal character (for debugging)
else:
# If the character is not a letter (A-F), it's a regular digit (0-9), so convert it directly to an integer
hex_p = int(hexx[-1 - i])

# Calculate the place value of the current hexadecimal digit (16^i) and multiply it by the decimal value (hex_p)
place = hex_p * (16 ** i)

# Add the place value to the final decimal result
den += place

# Output the final decimal value of the hexadecimal string
print(den)





Step-by-Step Explanation:
Hexadecimal Characters: The list hexx_list holds the characters A to F, which correspond to the numbers 10 to 15 in hexadecimal. In hexadecimal:

A = 10, B = 11, C = 12, D = 13, E = 14, F = 15.
Input Hexadecimal String: The string hexx = "AF" is the hexadecimal number that we want to convert to a decimal number.

Initialize Decimal Value: The variable den = 0 will be used to accumulate the final decimal value as we convert each hexadecimal digit.

Loop Over Hexadecimal String: The for loop goes through each character in the hexadecimal string hexx from right to left:

hexx[-1 - i] is used for accessing characters from the rightmost (least significant) to the leftmost (most significant).
For example, if hexx = "AF", on the first iteration, hexx[-1] gives "F", and on the second iteration, hexx[-2] gives "A".
Check for Hexadecimal Letters: The if condition checks whether the current character is one of the letters A to F:

If it is a letter, the index() method is used to find its position in hexx_list and convert it to its corresponding decimal value by adding 10 (since A=10, B=11, ..., F=15).
If the character is a regular number (0-9), it is directly converted to an integer using int().
Calculate Place Value: The value of the current hexadecimal digit is then multiplied by 16**i, where i is the position of the character from the right (0 for the rightmost digit, 1 for the second from the right, etc.). This is how place values work in hexadecimal:

For example, in AF:
F is in the "ones" place, so its value is multiplied by 16^0.
A is in the "sixteens" place, so its value is multiplied by 16^1.
Accumulate the Decimal Value: The place value of the current digit is added to the running total den.

Output the Final Result: After all digits are processed, the final decimal value is printed.

Example Walkthrough for "AF":
AF in hexadecimal is A*16 + F*1.
A corresponds to 10, so 10 * 16 = 160.
F corresponds to 15, so 15 * 1 = 15.
Total: 160 + 15 = 175.
The program will output 175 as the decimal equivalent of the hexadecimal string "AF".