Convert Bytes To Bits in Python

The task of converting bytes to bits in Python can be efficiently done by multiplying the number of bytes by 8, as 1 byte equals 8 bits. Additionally, methods like bit_length() and others can also be used to achieve this conversion.

Example:

def b2b(bv):
    return bv * 8

bv = 4
br = b2b(bv)

print(bv)
print(br)

4
32

Explanation: This code defines a function b2b that converts a given value (in bytes) to bits by multiplying it by 8. The input bv is the number of bytes, and the function returns the equivalent number of bits. The result is stored in br and printed alongside the original byte value bv.

Using bit_length() Method

In this example, the bytes object b'\x01\x23\x45\x67\x89\xAB\xCD\xEF' is converted to an integer using int.from_bytes() with 'big' byte order, and the number of bits is obtained using the bit_length() method.

bv = b'\x01\x23\x45\x67\x89\xAB\xCD\xEF'

br = int.from_bytes(bv, byteorder='big').bit_length()

print(br)

57

Explanation: This code converts a byte sequence bv into an integer using the from_bytes() method, specifying big-endian byte order. It then calculates the bit length of the resulting integer using bit_length(). The result, stored in br, is the number of bits required to represent the integer equivalent of the byte sequence and is printed.

Using Bitwise Shift

In this example, the bytes object b'\b\x16$@P' is converted to an integer by summing bitwise-shifted bytes, and the number of bits is obtained using the bit_length() method.

bv = b'\b\x16$@P'

br = sum(byte << (i * 8)
                  for i, byte in enumerate(reversed(bv)))

print( br.bit_length())

36

Explanation: This code calculates the bit length of a byte sequence bv. It uses a sum function to convert the byte sequence into an integer by shifting each byte's value left by multiples of 8 and adding them together. The bit_length() method then computes the number of bits required to represent the resulting integer. The result is printed as br.bit_length().

Handling Binary Data in Python

In some cases, we might be handling binary data directly and python gives the struct module for the conversions between the various types of required interpretations. In this case, the struct module is implemented to transform a binary data sequence into an integer and then it is transformed into the string form through bin. Therefore, it works the best with the raw binary data.

import struct

def b2b(bd):
    return bin(int.from_bytes(bd, byteorder='big'))[2:]

# Example: Convert binary data to bits
bd = b'\x01\x02\x03\x04'
br = b2b(bd)

print(bd)
print(br)

b'\x01\x02\x03\x04'
1000000100000001100000100

Explanation: This code defines a function b2b() that converts a byte sequence (bd) into a binary string. It uses the int.from_bytes() method to interpret the bytes as an integer, converts it to binary using bin(), and then removes the '0b' prefix by slicing the string. The result is printed as the original byte sequence and its equivalent binary form.