Counts the number of "1" and "0" bits in an input file

count-bits.py

#!/usr/bin/env python3
# Counts the number of "1" and "0" bits in an input file
import sys
bits_per_byte = 8


# Via: https://stackoverflow.com/a/1035456
def bytes_from_file(filename, chunksize=8192):
    with open(filename, "rb") as f:
        while True:
            chunk = f.read(chunksize)
            if chunk:
                for b in chunk:
                    yield b
            else:
                break


def count_ones(byte):
    bits = format(b, "0{}b".format(bits_per_byte))
    return len(list(filter(lambda x: x == "1", list(bits))))


filename = sys.argv[1]

ones_found = 0
zeros_found = 0
for b in bytes_from_file(filename):
    ones = count_ones(b)
    ones_found += ones
    zeros_found += bits_per_byte - ones

total_bits = ones_found + zeros_found
print(filename)
print("Total bits counted: {0}\nOnes:  {1} ({2:.3f})\nZeros: {3} ({4:.3f})\n".format(
    total_bits,
    ones_found,
    ones_found / total_bits,
    zeros_found,
    zeros_found / total_bits))