Binary Files

Reading and writing binary files is pretty straight forward.

from struct import pack, unpack

bin_filepath=r"c:\temp\my_bin_file.bin"

with open(bin_filepath, "wb") as bin_file:
    bin_file.write( pack('f', 31.323 ))
    bin_file.write( pack('I', 8462 ))
    # fill with zeroes
    count=245
    bin_file.write(pack('I'*count, *[0 for x in range(count)] ))
    # write a tuple
    my_val = (0.3, 3.2, 1.66, 9.431)
    bin_file.write( pack('ffff',  *my_val ) )

with open(bin_filepath, "rb") as bin_file:
    # read a float value
    # struct.unpack always tuple, even if only 1 value!
    float_value = unpack('f', bin_file.read(4))[0]
    # read an unsigned int
    int_value = unpack('I', bin_file.read(4))[0]
    # jump to position 245
    bin_file.seek(245)
    # read a 2-value tuble
    vector2_value = unpack('ff', bin_file.read(8))
    # read a 4-value tuple
    vector4_value = unpack('ffff', bin_file.read(16))

The format string consists of these:

Format	C Type	Python type	Standard size
x	pad byte	no value
c	char	bytes of length 1	1
b	signed char	integer	1
B	unsigned char	integer	1
?	_Bool	bool	1
h	short	integer	2
H	unsigned short	integer	2
i	int	integer	4
I	unsigned int	integer	4
l	long	integer	4
L	unsigned long	integer	4
q	long long	integer	8
Q	unsigned long long	integer	8
n	ssize_t	integer
N	size_t	integer
e	(6)	float	2
f	float	float	4
d	double	float	8
s	char[]	bytes
p	char[]	bytes
P	void*	integer

You can jump to file positions with seek