Binary data handling

Provides a mutable sequence of bytes for efficient binary manipulation.

Networking: modify binary data after reading from a file or socket; Cryptography: construct mutable buffers for encryption/decryption; Systems programming: build binary protocol packets before sending

Networking, file I/O, cryptography, low-level data processing.

bytearray(source_bytes)

bytearray(...)

source_bytes: bytes or iterable of integers 0-255

• .decode()
• .extend()
• memoryview
• struct.pack

• bytes(source_bytes) for immutable copy
• bytearray(n) for zero-filled buffer of length n

Assuming bytearray modifies the original bytes object; passing a string directly causes TypeError; assigning values outside 0-255 raises ValueError.

bytes() creates an immutable copy; memoryview provides a zero‑copy view of existing binary data.

Coming from languages where strings are mutable (e.g., JavaScript) one might expect similar in‑place behavior; in Python strings are immutable and bytearray is the mutable counterpart for binary data.

• bytes
• memoryview
• struct.pack
• bytearray methods

The elements of a bytearray are integers 0‑255; assigning out‑of‑range values raises ValueError; the object supports most list‑like methods but returns integers when indexed.

Enables efficient in‑place binary edits without allocating new objects for each modification.

Think of bytearray as a mutable list of bytes.

Ideal for building mutable binary buffers; indexing yields integers 0‑255.

Use memoryview for zero‑copy slicing or the struct module to pack/unpack binary structures.