How do you handle binary files in python?

Question 1

What distinguishes binary files from text files when handling them in Python?

Answer 1

Binary files (like images, audio, or executables) contain data as raw bytes, not human-readable characters.

Key Difference: Python does not automatically decode or encode characters when reading/writing binary files. You work directly with bytes objects rather than str objects. You must explicitly use binary modes (‘rb’, ‘wb’, etc.) when opening them.

Question 2

How do you open a file in binary mode for reading and writing?

Answer 2

Add the letter ‘b’ to the standard file mode (‘r’, ‘w’, ‘a’).
Reading binary: Use the mode ‘rb’.
Writing binary: Use the mode ‘wb’.
Appending binary: Use the mode ‘ab’.

with open("image.jpg", "rb") as f:
    # File operations here

Question 3

What type of data do file reading methods return in binary mode?

Answer 3

When reading a file opened in binary mode, methods like .read(), .readline(), and .readlines() return bytes objects, not strings.

with open("data.bin", "rb") as f:
    data = f.read(5)
    print(type(data)) # Output: <class 'bytes'>
    print(data)       # Output: b'\x01\x02\x03\x04\x05'

Question 4

How do you write data to a binary file?

Answer 4

You must provide a bytes object (or a byte array) to the .write() method when the file is opened in binary write mode (‘wb’ or ‘ab’).

data_to_write = b'\x48\x65\x6C\x6C\x6F' # Bytes representing "Hello"
with open("output.bin", "wb") as f:
    f.write(data_to_write)

Question 5

Can you use seek() and tell() in binary mode?

Answer 5

Yes, seek() and tell() work well in binary mode. In fact, binary mode is often preferred for precise positioning because the “offset” always refers to a specific byte count, unlike text mode where character encoding can make positioning ambiguous.

with open("file.bin", "rb") as f:
    f.seek(100) # Move exactly 100 bytes from the start
    current_pos = f.tell()
    print(f"Current byte position: {current_pos}")