How to Read-in Binary of a File in Python

Question

In Python, when I try to read in an executable file with 'rb', instead of getting the binary values I expected (0010001 etc.), I'm getting a series of letters and symbols that I do not know what to do with.

Ex: ???}????l?S??????V?d?\?hG???8?O=(A).e??????B??$????????:    ???Z?C'???|lP@.\P?!??9KRI??{F?AB???5!qtWI??8𜐮???!ᢉ?]?zъeF?̀z??/?n??

How would I access the binary numbers of a file in Python?

Any suggestions or help would be appreciated. Thank you in advance.

Answer 1

That is the binary. They are stored as bytes, and when you print them, they are interpreted as ASCII characters.

You can use the bin() function and the ord() function to see the actual binary codes.

for value in enumerate(data):
   print bin(ord(value))

Answer 2

Byte sequences in Python are represented using strings. The series of letters and symbols that you see when you print out a byte sequence is merely a printable representation of bytes that the string contains. To make use of this data, you usually manipulate it in some way to obtain a more useful representation.

You can use ord(x) or bin(x) to obtain decimal and binary representations, respectively:

>>> f = open('/tmp/IMG_5982.JPG', 'rb')
>>> data = f.read(10)
>>> data
'\x00\x00II*\x00\x08\x00\x00\x00'

>>> data[2]
'I'

>>> ord(data[2])
73

>>> hex(ord(data[2]))
'0x49'

>>> bin(ord(data[2]))
'0b1001001'

>>> f.close()

The 'b' flag that you pass to open() does not tell Python anything about how to represent the file contents. From the docs:

Append 'b' to the mode to open the file in binary mode, on systems that differentiate between binary and text files; on systems that don’t have this distinction, adding the 'b' has no effect.

Unless you just want to look at what the binary data from the file looks like, Mark Pilgrim's book, Dive Into Python, has an example of working with binary file formats. The example shows how you can read IDv1 tags from an MP3 file. The book's website seems to be down, so I'm linking to a mirror.