What's the Difference Between `globals()`, `locals()`, and `vars()` in Python?

Understanding the Differences Between globals(), locals(), and vars()

In Python, globals(), locals(), and vars() are functions that provide insights into the current program's namespace. Let's explore their distinctions:

globals()

• Purpose: Returns a dictionary of the global namespace.
• Behavior: Consistent, always returning the namespace dictionary for the current module.

locals()

• Purpose: Acquires a dictionary representing the current namespace.
• Behavior: Dynamic, depending on the caller's context.
• Inside a function: Returns a dictionary containing the current local variables and any closure variables. Multiple calls within the same stack frame return the same dictionary due to its association with the frame object's f_locals attribute. Updates to this dictionary are reflected in the local namespace, but assigning values directly to the dictionary does not modify the corresponding local variables.
• Outside a function: Returns the actual dictionary that serves as the current namespace. Changes to this dictionary are synchronized with the namespace, and vice versa.

vars()

• Purpose: Accepts an object as an argument and returns the dict attribute of that object.

• Behavior:

  • With no argument, it returns the dict of the current namespace (similar to locals() outside a function).
  • When provided an object, it retrieves the object's __dict__, typically containing its attribute data.
  • Updates to the returned dictionary influence the object's attributes, and conversely, changes to the object's attributes are reflected in the dictionary.

Key Note:

The behavior of locals() and vars() may vary across Python versions and implementations. In CPython 2.x, locals() could work differently with the use of "exec 'pass'".

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