In stack allocation, memory is allocated based on the function call stack or, in other words, based on the function currently being executed. When a function is called, its data types and variables are automatically allocated to the stack memory. Once the function is over, the data types are deallocated. Because of this, stack allocation is also known as temporary memory allocation. If the stack memory ends up becoming completely full, the program can no longer run and will throw a specific error called a stack overflow.

Stack Allocation

In heap allocation, memory is allocated based on the Python code written. It is a pile of memory available for the program. All objects are stored in the heap memory. When an object is created, it is allocated in the heap memory while referencing information for it is stored in the stack allocation when necessary. Heap memory is also what allows for global variables. Since heap memory is more dependent on the program, and thus the programmer, it also also less safe than stack memory and has the potential to create a memory leak. If the heap memory ends up becoming completely full, the program can no longer run and will throw a specific error called an out of memory error. Memory deallocation in the heap memory requires the use of a garbage collector.

Heap Allocation

Memory allocation in Python takes place in two parts:
- Stack Allocation
- Heap Allocation

Saint Olaf College

Data types in a program are likely to be allocated into memory when encountered in a program. Python's interpreter includes the Python memory manager, which handles how data types are stored and tracked in memory. The user has no control over this process. Memory allocation for each new variable is performed on demand by the Python memory manager automatically.

Memory Allocation

Geeks for Geeks is a website that offers information on a variety of programming languages, tips for coding interviews, and ideas for programming projects:  https://www.geeksforgeeks.org/python-programming-language/

Geeks for Geeks Python Programming Language

Types of Memory Allocation

PyArena is a structure that is part of the default CPython implementation of Python. It will store pointers to all memory given to it. The functions PyArena_Malloc() and PyArena_Free() are what control memory allocation and deallocation. PyArena also stores a linked-list of allocated memory blocks.

PyArena

In Python, standard operations like `Y = Y + X` do not update the variable `Y` in-place. Instead, Python first evaluates the expression `Y + X`, allocates new memory to host the resulting values, and then dereferences the tensor that `Y` used to point to, updating `Y` to point to this newly allocated memory location.

Learn Before

Related

Learn After