object() Function Complexity

The object() function creates the base object instance. It's the root of Python's object hierarchy.

Complexity Analysis

Case	Time	Space	Notes
Create object	O(1)	O(1)	Base instance
Attribute access	O(1)	O(1)	Default behavior
Subclassing	O(1)	O(1)	Class creation
Instance creation	O(1)	O(k)	k = init cost

Basic Usage

Create Base Object

# O(1) - create root object instance
obj = object()
# <object object at 0x...>

Object Type

# O(1) - all objects inherit from object
type(obj)  # <class 'object'>

# Check inheritance
isinstance(obj, object)  # True - all objects are objects

Basic Attributes

# O(1) - object has minimal attributes
obj = object()

# __class__ - type of object
obj.__class__  # <class 'object'>

# __doc__ - documentation
obj.__doc__  # "The base class of the class hierarchy."

# __hash__ - can be hashed
hash(obj)  # O(1)

Complexity Details

Object Creation

# O(1) - instant creation, minimal overhead
obj1 = object()  # O(1)
obj2 = object()  # O(1)

# Each call creates distinct instance
obj1 is obj2  # False - different objects
id(obj1) != id(obj2)  # Different memory addresses

Inheritance

# O(1) - all classes implicitly inherit from object
class MyClass:
    pass

obj = MyClass()  # O(1) - inherits from object

# Explicitly inherit
class MyClass(object):
    pass

obj = MyClass()  # O(1) - same behavior

Method Resolution Order

# O(1) - check MRO
class Base:
    pass

class Derived(Base):
    pass

# MRO lookup
Derived.__mro__  # (Derived, Base, object)

# object is always last

Common Patterns

Base Class for Shared Behavior

# O(1) - create base class
class Entity(object):
    def __init__(self, name):
        self.name = name  # O(1)

    def __str__(self):  # O(1)
        return f"Entity({self.name})"

# All subclasses inherit from object
class Person(Entity):
    pass

p = Person("Alice")  # O(1)

Duck Typing

# O(1) - leverage object interface
def describe(obj):
    # Works with any object
    return f"Type: {type(obj).__name__}, ID: {id(obj)}"

obj1 = object()
obj2 = "string"
obj3 = [1, 2, 3]

# All O(1) - all work with any object
describe(obj1)  # "Type: object, ID: ..."
describe(obj2)  # "Type: str, ID: ..."
describe(obj3)  # "Type: list, ID: ..."

Identity vs Equality

# O(1) - both operations
obj = object()
obj2 = object()

# Identity - is (checks same object)
obj is obj  # True - O(1)
obj is obj2  # False - O(1)

# Equality - == (default checks identity)
obj == obj  # True - O(1)
obj == obj2  # False - O(1) for base object

Practical Examples

Sentinel Value

# O(1) - use object as unique sentinel
_MISSING = object()  # Unique marker

def get_value(d, key):
    result = d.get(key, _MISSING)
    if result is _MISSING:
        # Handle missing case
        return None
    return result

data = {'a': 1, 'b': 2}
get_value(data, 'a')  # 1
get_value(data, 'c')  # None

Default Instance

# O(1) - use object as default
def process(config=None):
    if config is None:
        config = object()  # Default

    # Process with config
    return config

result = process()  # Uses default object

Type Checking

# O(1) - check if something is an object (everything is)
def is_object(x):
    return isinstance(x, object)

is_object(42)           # True - all things
is_object("string")     # True
is_object([1, 2])       # True
is_object(object())     # True

Object Interface

# O(1) - common object methods/attributes
obj = object()

# Type
type(obj)              # <class 'object'>

# Identity
id(obj)                # Memory address - O(1)

# Representation
str(obj)               # '<object object at 0x...>'
repr(obj)              # '<object object at 0x...>'

# Hashing
hash(obj)              # O(1) - based on id

# Class
obj.__class__          # <class 'object'>

# Documentation
obj.__doc__            # String

Class Creation

# O(1) - define custom classes
class CustomClass(object):
    """A custom class."""

    def __init__(self, value):
        self.value = value  # O(1)

    def __str__(self):
        return f"Custom({self.value})"

# Create instance
obj = CustomClass(42)  # O(1) - __init__ is O(1)

Multiple Inheritance

# O(1) - object at end of MRO
class A(object):
    pass

class B(object):
    pass

class C(A, B):  # Multiple inheritance
    pass

C.__mro__  # (C, A, B, object)
# object is always last

Attribute Access

# O(1) - default attribute behavior
obj = object()

# Can't add attributes to base object
try:
    obj.name = "test"  # AttributeError
except AttributeError:
    pass

# But custom classes can
class Custom:
    pass

c = Custom()
c.name = "test"  # O(1) - works

Edge Cases

Singleton Pattern

# O(1) - object() returns different instances
obj1 = object()
obj2 = object()

obj1 is obj2  # False - different instances

# Use object() for sentinel (unique identity)
NONE_SENTINEL = object()
EMPTY_SENTINEL = object()

# Each is unique
NONE_SENTINEL is EMPTY_SENTINEL  # False

Identity Checking

# O(1) - very fast identity check
obj = object()

# Identity with 'is' is fastest
obj is obj  # O(1) - just memory address comparison

# Equality with == (default is same as 'is' for object)
obj == obj  # O(1) - calls __eq__

# Hashing
hash(obj)  # O(1) - based on id

Inheritance Chain

# O(1) - traverse inheritance
class Root(object):
    pass

class Middle(Root):
    pass

class Leaf(Middle):
    pass

obj = Leaf()

# Check if object
isinstance(obj, object)  # True - O(1)

# Walk up MRO
Leaf.__mro__  # (Leaf, Middle, Root, object)

Comparison with type

# object - base class
# type - metaclass (creates classes)

obj = object()
MyClass = type('MyClass', (), {})  # Create class dynamically

type(obj)       # <class 'object'>
type(MyClass)   # <class 'type'>

# All classes are instances of type
# All instances are instances of object

Best Practices

✅ Do:

• Inherit from object explicitly for clarity (Python 2 compatibility)
• Use object() for sentinel values
• Rely on object's default behavior
• Check isinstance(x, object) for type checking

❌ Avoid:

• Creating instances of object() for storage (use custom classes)
• Trying to add attributes to object() instances
• Assuming object() instances have special behavior
• Overriding object methods unless necessary

Related Functions

• type() - Get or create types
• isinstance() - Check instance type
• id() - Get object identity

Version Notes

• Python 2.x: New-style classes inherit from object (old-style don't)
• Python 3.x: All classes implicitly inherit from object
• All versions: object() is the root of the hierarchy