🔡bytes, bytearray, and encode/decodeLESSON~12 min

bytes, bytearray, and encode/decode

While Python strings (str) deal with text (Unicode characters), bytes and bytearray deal with raw binary data — sequences of integers from 0 to 255. Understanding the distinction is crucial for network programming, file I/O, and working with binary formats.

The str vs bytes Distinction

In Python 3, str and bytes are completely separate types:

Creating bytes

bytes Operations

bytearray — Mutable bytes

bytearray is the mutable counterpart of bytes. Use it when you need to modify binary data in place:

Encoding: str → bytes

To convert text to bytes, you must specify an encoding — a mapping from characters to byte sequences. UTF-8 is the standard:

Decoding: bytes → str

Common Encodings

Encoding	Description	Characters
UTF-8	Variable-width, backward-compatible with ASCII	All Unicode
UTF-16	2 or 4 bytes per character	All Unicode
ASCII	1 byte per character	128 characters (English)
latin-1	1 byte per character	256 characters (Western European)
cp1252	Windows Western European	Similar to latin-1

Always use UTF-8 unless you have a specific reason not to.

Practical Use Cases

Reading/Writing Binary Files

Network Data

Checking File Signatures (Magic Bytes)

Knowledge Check

What does b"Hello"[0] return in Python?

Which method converts a str to bytes?

What is the key difference between bytes and bytearray?