CODEWITHSUNDEEP
pythonpython-3.xfloating-pointieee-754
zell
zell

Reputation: 10204

pythonic way to get the binary32 representation of a number (int, float, or double)

Related to Convert int to binary string in Python, I would like to know a pythonic way to get the IEEE-754 binary32 representation of a number of int, float, or double.

For example, 42.0 is to be converted to 1 10000100 01010000000000000000000

Upvotes: 0

Views: 286

Answers (2)

Wolf
Wolf

Reputation: 10238

Use struct.pack to create a 32-bit Big-endian floating point representation of value to get 4 bytes. Now iterate over these to format into zero-padded binary, and join the result to one string. Finally, insert space (' ') after sign bit and between exponent (8 bits) and fraction (23 bits).

import struct

def float32_bitstr(value):
    bits = ''.join([f"{b:08b}" for b in struct.pack('>f', value)])
    return bits[:1]+' '+bits[1:-23]+' '+bits[-23:]

print(f"{float32_bitstr(42.0)=}")

Output:

float32_bitstr(42.0)='0 10000100 01010000000000000000000'

BTW: For evaluating solutions, output via f"{expression=}" can be very handy.

Upvotes: 1

alexisdevarennes
alexisdevarennes

Reputation: 5642

Try this:

import struct

getBin = lambda x: x > 0 and str(bin(x))[2:] or "-" + str(bin(x))[3:]

def floatToBinary32(value):
    val = struct.unpack('I', struct.pack('f', value))[0]
    return getBin(val)

binstr = floatToBinary32(42.0)
print('Binary equivalent of 42.0:')
print(binstr + '\n')

Upvotes: 1

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