Reading and interpreting data from a binary file in Python

Try using the bytearray type (Python 2.6 and later), it's much better suited to dealing with byte data. Your try block would be just:

ba = bytearray(fh.read())for byte in ba:    print byte & 1

or to create a list of results:

low_bit_list = [byte & 1 for byte in bytearray(fh.read())]

This works because when you index a bytearray you just get back an integer (0-255), whereas if you just read a byte from the file you get back a single character string and so need to use ord to convert it to an integer.

If your file is too big to comfortably hold in memory (though I'm guessing it isn't) then an mmap could be used to create the bytearray from a buffer:

import mmapm = mmap.mmap(fh.fileno(), 0, access=mmap.ACCESS_READ)ba = bytearray(m)

You want to use ord instead of int:

if (ord(byte) & 0x01) == 0x01:

One way:

import arrayfilebytes= array.array('B')filebytes.fromfile(open("/tmp/test.txt", "rb"))if all(i & 1 for i in filebytes):    # all file bytes are odd

Another way:

fobj= open("/tmp/test.txt", "rb")try:    import functoolsexcept ImportError:    bytereader= lambda: fobj.read(1)else:    bytereader= functools.partial(fobj.read, 1)if all(ord(byte) & 1 for byte in iter(bytereader, '')):    # all bytes are oddfobj.close()