5. Binary file handling

Quiz: 0/5

When you save a file on your computer, it can be stored in two main formats:

1. Text files (like .txt or .csv), which contain human-readable characters.
2. Binary files (like images, videos, or program files), which store data in a way that only computers understand.

Since binary files aren't just plain text, we need special ways to read and write them in Python.

Working with binary files (rb, wb)

To work with binary files, we use modes:

• rb → Read a binary file
• wb → Write to a binary file

Example: Reading a binary file

Let’s say we have an image called picture.jpg. We can open and read it like this:

with open("picture.jpg", "rb") as file:
    content = file.read()  # Read the binary data
    print(content[:20])  # Print first 20 bytes (not human-readable)

This reads the file as raw data (not as text).

Example: Writing a binary file

If we want to save some binary data to a new file:

binary_data = b"Hello, this is binary data!"
with open("output.bin", "wb") as file:
    file.write(binary_data)  

This creates a new binary file and writes some raw data into it.

Handling images and other binary data

Since images, videos, and audio files are all binary files, we can use Python to copy, modify, or analyze them.

For example, let’s copy an image:

with open("source.jpg", "rb") as src, open("copy.jpg", "wb") as dest:
    dest.write(src.read())

This reads all the binary data from source.jpg and writes it into copy.jpg, making an exact copy.

Copying, moving, and deleting files with shutil

Python has a built-in module called shutil (short for shell utilities) that helps manage files.

Copying a file

import shutil
shutil.copy("source.jpg", "backup.jpg")  # Copies file

Moving a file

shutil.move("source.jpg", "new_folder/source.jpg")  # Moves file to another folder

Deleting a file

import os
os.remove("unwanted_file.bin")  # Deletes a file

Why is this useful?

• You can read and process images, videos, or any other binary data in Python.
• You can automate file management (copy, move, delete files).
• You can work with files safely using with open(...), so you don’t accidentally lose data.