What Are Entities in Python? Absolute Beginners Tutorial

When you write a Python program, you are constantly creating and working with entities — the named, reusable pieces that Python tracks for you. Understanding what an entity is, and the different forms it can take, gives you a mental model that applies to every Python program you will ever read or write.

Python is sometimes described as a language where everything is an object. That is accurate at a technical level, but for new learners the word "entity" is a more useful starting point. An entity is simply a named thing your program can work with — a piece of data, a block of reusable logic, a template for creating objects, or a file full of code you want to bring in. Once you can recognize each kind, you can read Python code written by other people with much greater confidence.

What Is an Entity in Python?

An entity is any program element that Python stores, names, and lets you reference later. When you write score = 100, the integer 100 is stored in memory and the name score is bound to it. That binding — name plus stored value — is the simplest form of an entity.

The Python data model formalizes this idea: every value Python stores is an object, and every object has three things — an identity (a unique address in memory), a type (what kind of thing it is), and a value (the actual data it holds). Entities are the objects your code gives names to.

You do not have to declare entities the way some other languages require. Python creates them the moment you assign a name to a value or define a function or class. The interpreter handles memory allocation for you.

# Three entities created in three lines
city = "Houston"        # variable entity — a string
age  = 34               # variable entity — an integer
pi   = 3.14159          # variable entity — a float

# You can inspect any entity's identity and type
print(id(city))         # a unique memory address number
print(type(age))        # <class 'int'>

The Five Core Entity Types

Python programs are built from five main kinds of entities. Each one plays a different role, and recognizing them by sight is a foundational skill.

Variables

A variable is a name bound to a value. It is created the moment you assign something to it and deleted when it goes out of scope or is explicitly removed. Variables can hold any type of value, and you can reassign them freely.

username = "alex"          # string variable
attempts = 0               # integer variable
is_logged_in = False       # boolean variable

# Reassigning a variable changes what it points to
attempts = attempts + 1
print(attempts)            # 1

Functions

A function is a named block of code that runs when called. In Python, functions are first-class entities — you can store them in variables, pass them to other functions, and return them from functions. They are defined with the def keyword.

def greet(name):
    return f"Hello, {name}!"

message = greet("Sam")
print(message)             # Hello, Sam!

# Functions are objects too — you can assign one to a variable
say_hi = greet
print(say_hi("Jordan"))    # Hello, Jordan!

Classes

A class is a blueprint for creating objects. It defines what data an object holds (attributes) and what actions it can perform (methods). Classes are defined with the class keyword, and individual objects created from a class are called instances.

class Dog:
    def __init__(self, name, breed):
        self.name = name
        self.breed = breed

    def bark(self):
        return f"{self.name} says: Woof!"

# Create two instances from the same class blueprint
dog1 = Dog("Rex", "Labrador")
dog2 = Dog("Mochi", "Shiba Inu")

print(dog1.bark())         # Rex says: Woof!
print(dog2.breed)          # Shiba Inu

Objects (Instances)

An object is a concrete instance created from a class. Every value in Python — integers, strings, lists, and instances of your own classes — is an object. When you write dog1 = Dog("Rex", "Labrador"), dog1 is the entity name and the Dog instance is the object it points to.

Modules

A module is a Python file you import into your program. When imported, it becomes an entity in the current namespace. You access the contents of a module using dot notation: module_name.function_name().

import math
import random

# math and random are now module entities in this program
print(math.sqrt(144))      # 12.0
print(random.randint(1, 6)) # a random number between 1 and 6

Identity, Type, and Value

Every Python entity has three attributes built into the language itself. Knowing them helps you understand why two variables can hold the same value but still be different objects, and why some operations change an object while others return a new one.

Identity is the unique address Python assigns to an object in memory. You read it with id(). Two names can share an identity if they point to the same object — this is called an alias. The is operator checks identity, not equality.

Type is the category of the object: int, str, list, Dog, and so on. You read it with type(). The type controls what operations are valid — for example, you can call .upper() on a string but not on an integer.

Value is the actual data stored in the object. The == operator compares values. Two separate objects can be equal in value without being the same object in memory.

a = [1, 2, 3]
b = [1, 2, 3]
c = a              # c and a point to the same object (alias)

print(a == b)      # True  — same value
print(a is b)      # False — different objects in memory
print(a is c)      # True  — same object

print(id(a))
print(id(b))       # different from id(a)
print(id(c))       # same as id(a)

"In Python, everything is an object." — Python Software Foundation documentation

Python Learning Summary Points

1. An entity in Python is any named element the interpreter stores and tracks — including variables, functions, classes, objects, and modules. Every entity is an object with an identity, a type, and a value.
2. The five core entity types each serve a different role: variables hold data, functions hold logic, classes define object blueprints, objects hold instance-specific data, and modules group related code in separate files.
3. Python's three built-in inspection tools — id(), type(), and == vs is — let you examine any entity's identity, type, and value at runtime, which is invaluable when debugging aliasing issues or unexpected behavior.

With these five entity types in your vocabulary, you have a framework for understanding every piece of Python code you encounter. Variables name your data, functions package your logic, classes describe your object blueprints, instances bring those blueprints to life, and modules let you organize and share code across files. The rest of Python builds on these building blocks.