How to convert a string to a Python class object?

Let's understand the title: converting a string to a Python class means accessing a Python class using its name stored as a string, allowing dynamic creation of objects at runtime. In this article, we will discuss different ways to convert a string to a Python class object.

Using globals() Function

The globals() function is used to convert a string to a Python class object when a class is in global scope.

class Bike:
   def start(self):
      print("Bike started!")

class_name = "Bike"
cls = globals()[class_name]  # Convert string to class
obj = cls()
obj.start()
print(type(obj))

Following is the output of the above code -

Bike started!
<class '__main__.Bike'>

Using locals() Function

The locals() function is used to convert a string to a Python class object when a class is in local scope (like inside a function).

def create_object():
   class Animal:
      def bark(self):
         print("Iam an Animal")
   class_name = "Animal"
   cls = locals()[class_name]
   obj = cls()
   obj.bark()
   print(type(obj))

create_object()

Following is the output of the above code -

Iam an Animal
<class '__main__.create_object.<locals>.Animal'>

Using getattr() Function

The getattr() is used when the class is defined in another module. Let us assume we have the following program in a file named "Python.py".

# In another file (say `Python.py`)
class Tutorialspoint:
   def Python(self):
      print("Hello welcome to Python Tutorial")

We can use the getattr() function to create its instance if the call is created in a separate module - 

import Python

class_name = "Tutorialspoint"
cls = getattr(Python, class_name)
obj = cls()
obj.Python()

Following is the output of the above code -

Hello welcome to Python Tutorial
<class 'Python.Tutorialspoint'>