Here there is no attribute called "a" in the class Node then what is the meaning of x.a ? Can object name contain the character "." in python ?
class Node : def __init__(self, left = None, data = None, right = None) : self.left = left self.data = data self.right = right x = Node(50) x.a = Node(40) Python is a Dynamically Typed Language. Which means you can set the value of any variable without having to declare that variable.
In your code snippet, x = Node(50) is creating a new node class object with x.left assigned to 50.
Now by doing x.a = Node(40), we are just defining a new attribute of the object x with name a, which will be a Node class object with left value of 50.
If you do dir(x) it will give you something like this,
['__class__', '__delattr__', #Some other attributes '__weakref__', 'a', 'data', 'left', 'right'] If you take a look at the last 4 attributes you can see that a is now also added as an attribute of the x object.
if you do x.new_attribute = Node(10,20,30) when new_attribute isn't present in the object then python will just create a new attribute inside the x object with the name new_attribute & assign it the value of Node(10,20,30).
