How to write int array [0,1,2,...] in binary to a file using Python script

Question

I'm new to Python. I want to generate a 100K binary file. The file contents will be (in hex):

00000000 00000001 00000002 00000003
00000004 00000005 00000006 00000007
...

I read some examples, but they all write a string to a text file. That's not what I want.

Do you want literal zeros, commas, and x's in your file? If so, should there be spaces after the commas? — user2357112, Mar 28 '14 at 04:16

score 4 · Accepted Answer · edited May 23 '17 at 10:31

4

First, you can use the struct module to pack each number into a four-byte binary string. (See: Convert a Python int into a big-endian string of bytes)

Then, just loop from 0-25,000 and write each number to your file. Since each number is four bytes, this will produce a 100K file. For example:

import struct

f = open("filename","wb")
for i in range(25000):
    f.write(struct.pack('>I', i))
f.close()

edited May 23 '17 at 10:31

Community

answered Mar 28 '14 at 04:14

Carter Sande

if all of his values will fit in 8 bits, he could just use `chr`, correct? – Broseph Mar 28 '14 at 04:22
@Broseph He could just use `chr` if he wanted 8-bit numbers, but he wanted 32-bit binary numbers in the file. – Carter Sande Mar 28 '14 at 04:24
1

Oh yes, my mistake. It is still possible to do this without struct, but that would be pointless. Unless this is homework and the teacher wants them to play with bits, lol. – Broseph Mar 28 '14 at 04:26

1 Answers1