Reference Counting

Reference counting works by counting the number of times an object is referenced by other objects in the system. When references to an object are removed, the reference count for an object is decremented. When the reference count becomes zero, the object is deallocated.

For example, Let’s suppose there are two or more variables that have the same value, so, what Python virtual machine does is, rather than creating another object of the same value in the private heap, it actually makes the second variable point to that originally existing value in the private heap. Therefore, in the case of classes, having a number of references may occupy a large amount of space in the memory, in such a case referencing counting is highly beneficial to preserve the memory to be available for other objects

Example:

When x = 10 is executed an integer object 10 is created in memory and its reference is assigned to variable x, this is because everything is object in Python.

Let’s verify if it’s true

Output:

x and y refer to the same object

In the above example, y = x will create another reference variable y which will refer to the same object because Python optimizes memory utilization by allocation the same object reference to a new variable if the object already exists with the same value.

Now, let’s change the value of x and see what happens.

Output:

x and y do not refer to the same object

So now x refer to a new object x and the link between x and 10 disconnected but y still refer to 10.

Understanding Memory allocation is important to any software developer as writing efficient code means writing a memory-efficient code. Memory allocation can be defined as allocating a block of space in the computer memory to a program. In Python memory allocation and deallocation method is automatic as the Python developers created a garbage collector for Python so that the user does not have to do manual garbage collection.