A Python namespaces is a mapping from names to objects. It works like a dictionary where keys are object names and values are the objects themselves.

A namespace is a container that holds the currently defined symbolic names and the objects each name references.

These namespaces have differing lifetimes. As Python executes a program, it creates namespaces as necessary and removes them when it no longer needs them.

Four Different Namespace Available:

1. Built-in
2. Local
3. Gobal
4. Enclosing or nonlocal

Built-In Namespace

• ex. Exception, Primitive Types, sort, reverse etc.

>>> dir(__builtins__)
[
    'ArithmeticError',
    'AssertionError',
    'AttributeError',
    'BaseException',
    ...
    'super',
    'tuple',
    'type',
    'vars',
    'zip'
]

Global Namespace

• The global namespace contains the names defined at the module level.

• Python creates a main global namespace when the main program’s body starts.

• Globals are seperate to module

Local Namespace

• function level namespace
• on enter of function -> create a namespace, on exit of a function -> delete the namespace.

Enclosing or Non Local Namespace

>>> global_variable = "global"

>>> def outer_func():
...     # Nonlocal scope
...     nonlocal_variable = "nonlocal"
...     def inner_func():
...         # Local scope
...         local_variable = "local"
...         print(f"Hi from the '{local_variable}' scope!")
...         print(f"Hi from the '{nonlocal_variable}' scope!")
...         print(f"Hi from the '{global_variable}' scope!")
...     inner_func()
...

>>> outer_func()
Hi from the 'local' scope!
Hi from the 'nonlocal' scope!
Hi from the 'global' scope!

The LEGB Rule for Searching Name

LOCAL > ENCLOSING > GLOBAL > BUILTIN