Writing integer to binary file

Question

I wrote a python function that writes a integer to a file in binary form. But are there any ways that I can reduce the number of steps, is there a more efficient way to write a integer to a file?

def IntWrite(FileName, Integer):
 #convert to hexadecimal
 data = str('{0:0x}'.format(Integer))
 #pad number if odd length
 if(len(data) % 2 != 0):
 data="0"+data
 #split into chucks of two
 info = [data[i:i+2] for i in range(0, len(data), 2)]
 #convert each chuck to a byte
 data2 = "".join([chr(int(a, 16)) for a in info])
 #write to file
 file(FileName, "wb").write(data2)
#convert back to integer
def IntRead(FileName):
 RawData = file(FileName, "rb").read()
 HexData = "".join(['{0:0x}'.format(ord(b)) for b in RawData])
 return int(HexData, 16)
IntWrite("int_data.txt", 100000)
print IntRead("int_data.txt")

• Michael Urman: This is more of a SO question. See struct.pack, struct.unpack, in this case with a format character of i or I, unless you need more than 32 bits.
• 200_success: ... but it's also acceptable as a Code Review question.
• Michael Urman: Sure, especially if there is a need to handle arbitrarily large integers, which the original code seems to offer. Otherwise the best code is that which you don't have to write. :)

Answer 1

Python comes with a built-in pickle module for serialization:

>>> import pickle
>>> with open('data', 'wb') as f: pickle.dump(9 ** 33, f)
>>> with open('data', 'rb') as f: print(pickle.load(f))
30903154382632612361920641803529

(P.S. I wouldn't use a filename ending with .txt to store binary data.)

• 200_success: Note that pickle's binary format is incompatible with the original question.
• Gareth Rees: Yes, that's right: I'm assuming here that the OP is starting from scratch.