Variables and Name Binding

15 min · Beginner

In Python, a variable is not a typed memory box. Instead, a variable is a name tag bound to an object in memory.

Variables as name tags

Variable is a name that refers to an object in memory. In Python the name has no type; the object it points to holds the type and the value.

When you write an assignment, Python creates an object in memory and binds the variable name to that object.

Python

total_score = 95print(total_score)

Example 1 · Three variables, three types

Python

1course_name = "Python Placement Track"2modules_count = 123is_active = True4
5print(course_name)6print(modules_count)7print(is_active)8print(type(course_name))

Output

Python Placement Track
12
True
<class 'str'>

What this code does

course_name references a string object.
modules_count references an integer object.
is_active references a boolean value True.
type(course_name) prints <class 'str'>.

Unlike statically typed languages like Java or C++, you do not declare a type such as int or String. The object holds the type, not the variable name.

Dynamic rebinding

Rebinding is pointing an existing name at a different object. The old object is not changed; the name simply refers to something new.

Because variables are name tags, you can rebind a name to an object of a completely different type at any time.

Python

status = "pending"print(status)status = 200print(status)

Example 2 · Two names, one object

Python

price = 100same_price = priceprice = 120print(price)print(same_price)

Output

120
100

What this code does

same_price = price makes both names point to the same object, 100.
price = 120 rebinds only price to a new object.
same_price still points to 100, so it keeps its value.

Python updates the reference smoothly. While dynamic typing gives great flexibility, write clear code so variable roles stay predictable.

PEP 8 naming rules and snake_case

PEP 8 is the official Python style guide. It asks for snake_case names: lowercase words joined by underscores, such as order_total.

The official Python style guide, PEP 8, recommends snake_case for variable and function names.

Use snake_case: write order_total and user_email, not orderTotal or OrderTotal.
Start with a letter or underscore: user_1 is valid; 1_user raises a SyntaxError.
Avoid Python keywords: names like def, class, return and if are reserved.
Constants use UPPER_SNAKE_CASE: write MAX_RETRIES = 3 for values that should not change.

Inspecting types with type()

Type is the kind of an object, such as int, float, str or bool. It decides what the object can hold and what you can do with it.

Use the built-in type() function whenever you want to check what kind of object a variable currently points to.

Python

price = 49.99print(type(price))

Example 3 · The type follows the object

Python

status = "pending"print(type(status))status = 200print(type(status))

Output

<class 'str'>
<class 'int'>

What this code does

At first status points to a string, so type shows str.
After rebinding it points to an integer, so type shows int.
The name never had a type; the object did.

Python displays <class 'float'>, confirming that price references a floating-point number object.

Next step

Check your understanding

9 quick questions

Variables and Name Binding

15 min · Beginner

Need help? Ask a tutor

In Python, a variable is not a typed memory box. Instead, a variable is a name tag bound to an object in memory.

Variables as name tags

Variable is a name that refers to an object in memory. In Python the name has no type; the object it points to holds the type and the value.

When you write an assignment, Python creates an object in memory and binds the variable name to that object.

Python

total_score = 95print(total_score)

Example 1 · Three variables, three types

Python

1course_name = "Python Placement Track"2modules_count = 123is_active = True4
5print(course_name)6print(modules_count)7print(is_active)8print(type(course_name))

Output

Python Placement Track
12
True
<class 'str'>

What this code does

course_name references a string object.
modules_count references an integer object.
is_active references a boolean value True.
type(course_name) prints <class 'str'>.

Unlike statically typed languages like Java or C++, you do not declare a type such as int or String. The object holds the type, not the variable name.

Dynamic rebinding

Rebinding is pointing an existing name at a different object. The old object is not changed; the name simply refers to something new.

Because variables are name tags, you can rebind a name to an object of a completely different type at any time.

Python

status = "pending"print(status)status = 200print(status)

Example 2 · Two names, one object

Python

price = 100same_price = priceprice = 120print(price)print(same_price)

Output

120
100

What this code does

same_price = price makes both names point to the same object, 100.
price = 120 rebinds only price to a new object.
same_price still points to 100, so it keeps its value.

Python updates the reference smoothly. While dynamic typing gives great flexibility, write clear code so variable roles stay predictable.

PEP 8 naming rules and snake_case

PEP 8 is the official Python style guide. It asks for snake_case names: lowercase words joined by underscores, such as order_total.

The official Python style guide, PEP 8, recommends snake_case for variable and function names.

Use snake_case: write order_total and user_email, not orderTotal or OrderTotal.
Start with a letter or underscore: user_1 is valid; 1_user raises a SyntaxError.
Avoid Python keywords: names like def, class, return and if are reserved.
Constants use UPPER_SNAKE_CASE: write MAX_RETRIES = 3 for values that should not change.

Inspecting types with type()

Type is the kind of an object, such as int, float, str or bool. It decides what the object can hold and what you can do with it.

Use the built-in type() function whenever you want to check what kind of object a variable currently points to.

Python

price = 49.99print(type(price))

Example 3 · The type follows the object

Python

status = "pending"print(type(status))status = 200print(type(status))

Output

<class 'str'>
<class 'int'>

What this code does

At first status points to a string, so type shows str.
After rebinding it points to an integer, so type shows int.
The name never had a type; the object did.

Python displays <class 'float'>, confirming that price references a floating-point number object.

Next step

Check your understanding

9 quick questions