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Python () Function

The vars() function returns the __dict__ attribute of an object, i.e. a dictionary containing the object's changeable attributes.

Syntax​

vars(object)

vars() Parameters​

Python vars() function parameters:

ParameterConditionDescription
objectOptionalThe object whose __dict__ attribute is to be returned

vars() Return Value​

Python vars() function returns:

  • __dict__ attribute of the given object.
  • dictionary of the current local scope if no object is specified.
danger

TypeError is raised if the object passed does not have the __dict__ attribute.

Examples​

Example 1: Using vars() without an Argument​

When called without arguments, vars() returns a dictionary containing the local symbol table, which can be useful for introspection of the current local scope.

# vars() with no argument
print(vars())

output

{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>}

Example 2: Using vars() with a Class Instance​

For example, consider the following Person class:

class Person:
    def __init__(self, name="Tom", age=25, sex="Male"):
        self.name = name
        self.age = age
        self.sex = sex

person = Person()
print(vars(person))

output

{'name': 'Tom', 'age': 25, 'sex': 'Male'}

Observe that vars(person) returns the __dict__ attribute of the Person instance, which is a dictionary containing the attributes name, age, and sex along with their values.

Example 3: Using vars() with Local Variables​

The vars() function can be used within a function to introspect local variables and their values.

In the following example, the output includes the local variables a, b and result, showing the dynamic nature of vars().

def calculate_sum(a, b):
    result = a + b
    variables = vars()
    return variables

sum_variables = calculate_sum(5,  7)
print(sum_variables)

output

{'a': 5, 'b': 7, 'result': 12}

Example 4: vars() with Objects Without __dict__ Attribute​

Attempting to use vars() function with objects that do not have a __dict__ attribute will result in a TypeError!

For example, strings and numbers do not have __dict__ attribute.

string = "Tom"

print(vars(string)) # raise a TypeError

output

Traceback (most recent call last):
  File "main.py", line 3, in <module>
    print(vars(string)) # raise a TypeError
TypeError: vars() argument must have __dict__ attribute
number = 132

print(vars(number)) # raise a TypeError

output

Traceback (most recent call last):
  File "main.py", line 3, in <module>
    print(vars(number)) # raise a TypeError
TypeError: vars() argument must have __dict__ attribute

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