Python type()

Python’s type() function serves two distinct purposes depending on how many arguments you pass. With a single argument, it returns the type of the given object as a type object (for example, <class 'int'> or <class 'str'>). With three arguments – a name, a tuple of base classes, and a dictionary of attributes – it dynamically creates and returns a new type (class) at runtime. The single-argument form is by far the most common and is used for debugging, logging, input validation, and understanding what kind of data you are working with. The three-argument form is an advanced feature used in metaprogramming, framework construction, and dynamic class generation. For type checking in production code, Python isinstance() is generally preferred over type() because it respects inheritance hierarchies. If you need to convert a value to a specific type, see Python int(), Python str(), or Python float().

What does type() return?

With one argument, type() returns the type of the object as a class. With three arguments (name, bases, dict), it returns a newly created type object that acts as a class definition.

When should you use type()?

Use type() when you need to inspect the exact type of an object during debugging or logging. For conditional type checking in application logic, prefer isinstance() since it handles subclasses correctly. Use the three-argument form only when you need to create classes dynamically at runtime.

The type() function has two separate syntax to return different results
The syntax of type() function is:

type(object)
type(name, bases, dict)

type() with single parameter

• object - Name of the object whose type has to return.

Example 1: type() function with object parameter.

a = 1
print(type(a))

b = 3.14
print(type(b))

c = "Python"
print(type(c))

my_list = [1,2,3]
print(type(my_list))

my_dict = { "a" : 1, "b" : 2, "c" : 3}
print(type(my_dict))

Output:

<class 'int'>
<class 'float'>
<class 'str'>
<class 'list'>
<class 'dict'>

type() with multiple parameters

When we pass these parameters to the type() function it will return a new type object.

• name - A name of the class which later becomes the __name__ attribute.
• bases (Optional) - A tuple that specifies the base classes.
• dict - A dictionary that specifies the namespace with the definition for the class.

Example 2: type() function with multiple parameters.

o1 = type('X', (object,), dict(a='Coco', b=4))

print(type(o1))
print(vars(o1))

class test:
  a = 'Coco'
  b = 4
  
o2 = type('Y', (test,), dict(a='Coco', b=4))
print(type(o2))
print(vars(o2))

Output:

<class 'type'>
{'a': 'Coco', 'b': 4, '__module__': '__main__', '__dict__': <attribute '__dict__' of 'X' objects>, '__weakref__': <attribute '__weakref__' of 'X' objects>, '__doc__': None}
<class 'type'>
{'a': 'Coco', 'b': 4, '__module__': '__main__', '__doc__': None}

In the program, we have used the Python vars() function which returns the __dict__ attribute. __dict__ is used to store an object’s writable attributes.

Common Use Cases

Debugging and logging. During development, type() helps you quickly identify what kind of data a variable holds. Printing type(variable) in a log statement can reveal unexpected types that cause bugs, especially when working with data from external APIs or user input.

Dynamic class creation in frameworks. ORMs (Object-Relational Mappers) and web frameworks use the three-argument form of type() to generate model classes or form classes dynamically based on configuration files or database schemas, avoiding repetitive boilerplate code.

Type-based dispatching. In situations where you need to handle different types differently (and isinstance() is not appropriate), type() lets you compare exact types. For example, if type(value) is int ensures the value is exactly an integer and not a Boolean (since bool is a subclass of int).

Related Functions

• Python isinstance() – check if an object is an instance of a class or its subclasses.
• Python callable() – check if an object appears to be callable.
• Python bool() – convert a value to Boolean (bool is a subclass of int).