Python bytearray

Overview

bytearray is an important built-in class in Python that represents a mutable sequence of bytes.

1. Basic Characteristics

bytearray is similar to bytes, but unlike bytes, bytearray is mutable.

# Create a bytearray
ba = bytearray(b'Hello')
print(ba)  # Output: bytearray(b'Hello')
print(type(ba))  # Output: <class 'bytearray'>

2. Methods to Create bytearray

Create from bytes object

ba1 = bytearray(b'Hello')
print(ba1)  # bytearray(b'Hello')

Create from string (encoding required)

ba2 = bytearray('Hello', 'utf-8')
print(ba2)  # bytearray(b'Hello')

Create empty bytearray of specified length

ba3 = bytearray(5)
print(ba3)  # bytearray(b'\x00\x00\x00\x00\x00')

Create from iterable object

ba4 = bytearray([65, 66, 67, 68])  # ASCII: A, B, C, D
print(ba4)  # bytearray(b'ABCD')

3. Mutability Demonstration

# bytes is immutable (will cause error)
b = b'Hello'
# b[0] = 74  # TypeError: 'bytes' object does not support item assignment

# bytearray is mutable
ba = bytearray(b'Hello')
ba[0] = 74  # ASCII code for 'J'
print(ba)  # bytearray(b'Jello')

4. Common Operations

Add elements

ba = bytearray(b'Hello')
ba.append(33)  # ASCII code for '!'
print(ba)  # bytearray(b'Hello!')

Extend bytearray

ba = bytearray(b'Hello')
ba.extend(b' World')
print(ba)  # bytearray(b'Hello World')

Convert to other types

ba = bytearray(b'Hello')
# Convert to bytes
bytes_obj = bytes(ba)
print(bytes_obj)  # b'Hello'

# Convert to string
string = ba.decode('utf-8')
print(string)  # 'Hello'