Exercise 09-40:
Modify the visualize.py program to print only the first 512 bytes of the file.
Answer:
##############################################################################
# Python From Scratch
# Author: Nilo Ney Coutinho Menezes
# Editora Novatec (c) 2010-2025 - LogiKraft 2025
# Site: https://pythonfromscratch.com
# ISBN: 978-85-7522-949-1 (Paperback), 978-85-7522-950-7 (hardcover), 978-85-7522-951-4 (ebook)
#
# File: chapter 09/exercise-09-40.py.py
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import sys
import itertools
def print_bytes(image, bytes_per_line=16):
for b in itertools.batched(image, bytes_per_line):
hex_view = " ".join([f"{v:02x}" for v in b])
tview = "".join([chr(v) if chr(v).isprintable() else "." for v in b])
print(f"{hex_view} {" " * 3 * (bytes_per_line - len(b))}{tview}")
if __name__ == "__main__":
with open(sys.argv[1], "rb") as f:
image = f.read(512) # Doesn't read the entire file, only the first 512 bytes
print_bytes(image)