Convert a Decimal Number to Hexadecimal

Decimal and hexadecimal are two different ways of representing numbers. Decimal uses base-10 (0-9), while hexadecimal uses base-16 (0-9 and A-F, where A=10, B=11, C=12, D=13, E=14, and F=15). Converting between these systems is a common task in programming, particularly when working with memory addresses, color codes, or data representation at a lower level. This post will show you how to easily convert decimal numbers to hexadecimal in Python.

Method 1: Using the hex() Function

Python provides a built-in function, hex(), that directly converts a decimal integer to its hexadecimal representation. The function returns a string starting with “0x”, indicating it’s a hexadecimal value.

decimal_number = 255

hexadecimal_number = hex(decimal_number)

print(f"The hexadecimal representation of {decimal_number} is: {hexadecimal_number}") 

This code will output:

The hexadecimal representation of 255 is: 0xff

If you don’t want the “0x” prefix, you can easily slice it off:

decimal_number = 255

hexadecimal_number = hex(decimal_number)[2:] #Slice from index 2 onwards

print(f"The hexadecimal representation of {decimal_number} is: {hexadecimal_number}")

This will output:

The hexadecimal representation of 255 is: ff

Method 2: Using the format() Function

The format() function offers another flexible approach. It allows you to specify the base for number conversion using the 'x' or 'X' format specifier (lowercase ‘x’ for lowercase hexadecimal letters, uppercase ‘X’ for uppercase).

decimal_number = 255

hexadecimal_number = format(decimal_number, 'x') #Lowercase hexadecimal

print(f"The hexadecimal representation of {decimal_number} is: {hexadecimal_number}")

hexadecimal_number_uppercase = format(decimal_number, 'X') #Uppercase hexadecimal

print(f"The uppercase hexadecimal representation of {decimal_number} is: {hexadecimal_number_uppercase}")

This will output:

The hexadecimal representation of 255 is: ff
The uppercase hexadecimal representation of 255 is: FF

Method 3: Manual Conversion (for educational purposes)

While the built-in functions are the most efficient, understanding the underlying process can be beneficial. Here’s a manual conversion method, illustrating the algorithm:

def decimal_to_hex(decimal_num):
    hex_digits = "0123456789ABCDEF"
    if decimal_num == 0:
        return "0"
    hex_string = ""
    while decimal_num > 0:
        remainder = decimal_num % 16
        hex_string = hex_digits[remainder] + hex_string
        decimal_num //= 16
    return hex_string

decimal_number = 4567

hexadecimal_number = decimal_to_hex(decimal_number)

print(f"The hexadecimal representation of {decimal_number} is: {hexadecimal_number}")

This will output:

The hexadecimal representation of 4567 is: 11D7

This manual approach demonstrates the process of repeatedly dividing by 16 and collecting the remainders. However, for practical applications, the built-in hex() and format() functions are strongly recommended for their efficiency and readability.