Python how to write in binary mode a list of hexadecimals?

Question

I have a string of hex representations of text that I need to write to a file.

toWrite = "020203480A"

with open("example.bin", "w") as file:
   file.write(chr(int(toWrite, 16)))

The problem is that whenever I write LF (0A) Windows automatically adds CR (0D). I know because I open the file in HxD I read 02 02 03 48 0D 0A.

How do I prevent Windows from adding CR before LF?

Answer 1

If you want to directly write bytes to a file without localized line ending behavior, open the file in binary mode instead of text mode:

toWrite = "020203480A"

# Note "wb" instead of "w"
with open("example.bin", "wb") as file:
   file.write(bytes.fromhex(toWrite))

or, using pathlib to automatically handle opening and closing the file:

from pathlib import Path

toWrite = "020203480A"
p = Path("example.bin")
p.write_bytes(bytes.fromhex(toWrite))