5 Best Ways to Convert Python Float to Hexadecimal

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💡 Problem Formulation: Converting a floating-point number to its hexadecimal representation can be necessary when dealing with low-level data processing or interfacing with systems that require hexadecimal values. In Python, this process can be achieved in several ways. For example, if we have the float 9.15625, we would want to express it in its hexadecimal form, which is 0x1.2c00000000000p+3.

Method 1: Using float.hex()

Python’s built-in float type provides a method called hex(), which converts a floating-point number to its hexadecimal representation as a string. This method produces a hexadecimal string that is precise and easy to read, which is compliant with the format specified in the IEEE 754 standard.

Here’s an example:

floating_number = 9.15625
hex_representation = floating_number.hex()
print(hex_representation)

Output:

0x1.2c00000000000p+3

This code converts the floating-point number 9.15625 to its hexadecimal representation. This hexadecimal string is the exact value that the float.hex() method yields, and it follows the IEEE 754 format for floating-point numbers.

Method 2: Using struct.pack() and binascii.hexlify()

Python’s struct module can pack the float into binary data, and the binascii module can subsequently convert the binary data into a hexadecimal string. This approach is more tailored for binary data handling and can be used when working with binary file formats.

Here’s an example:

import struct
import binascii

floating_number = 9.15625
binary_data = struct.pack('>d', floating_number)
hex_representation = binascii.hexlify(binary_data)
print(hex_representation.decode())

Output:

4022c00000000000

In this example, the float is packed into a binary format using big-endian byte order (indicated by ‘>’) and a double precision format (‘d’). Then binascii.hexlify() creates a hexadecimal representation, which is decoded from bytes to a string for readability.

Method 3: Using Format Specifiers

The format() function in Python, used with specific format specifiers, can convert a float to its hexadecimal representation. The format specifier 'a' is used for hexadecimal floating-point numbers, prefixed with an ‘0x’.

Here’s an example:

floating_number = 9.15625
hex_representation = format(floating_number, 'a')
print(hex_representation)

Output:

0x1.2cp+3

In this code snippet, the format specifier ‘a’ is responsible for converting the float to a hexadecimal string. Note that the exponent is written in decimal and the letter ‘p’ indicates the power of two for the exponent.

Method 4: Using float.fromhex() and hex()

An indirect way of achieving the conversion is to first use float.fromhex() to convert a hexadecimal string into a floating-point number, and then use hex() on an integer to get its hexadecimal representation. However, it’s important to note that this method might not maintain the exact floating-point precision during the conversion.

Here’s an example:

hex_str = '0x1.2cp+3'
floating_number = float.fromhex(hex_str)
int_representation = int(floating_number)
hex_representation = hex(int_representation)
print(hex_representation)

Output:

0x9

This method converts a hexadecimal string back to a float and then to an integer to get an approximate hexadecimal representation of the original float. However, this method only works with the fractional part truncated and should be used with caution when exact precision is needed.

Bonus One-Liner Method 5: Lambda Function

A lambda function can be constructed in Python to encapsulate the float.hex() conversion into a reusable and concise one-liner. This is beneficial for repeated conversions within codebases that value brevity.

Here’s an example:

hexify = lambda x: x.hex()
print(hexify(9.15625))

Output:

0x1.2c00000000000p+3

The lambda function named hexify here takes a float as input and returns its hexadecimal representation using the hex() method from the Python float type.

Summary/Discussion

  • Method 1: float.hex(). Direct and precise. Maintains IEEE 754 standard compliance. Limited to Python’s default float precision.
  • Method 2: struct.pack() and binascii.hexlify(). Useful for binary data. Provides a hex string with no floating-point specific formatting. Might require additional manipulation for representation consistency with other methods.
  • Method 3: Format Specifiers. Simple and effective for string formatting. May not be as immediately apparent to those unfamiliar with format specifiers.
  • Method 4: float.fromhex() and hex(). Not recommended for precise conversions due to potential float to integer precision loss.
  • Method 5: Lambda Function. Allows for the succinct expression of conversion in code that already uses float.hex(). Offers no functional advantage over direct use of float.hex().