Python Behind the Scenes - Understanding Code Execution Flow

Prakash Vinukonda — Sat, 16 Aug 2025 13:05:50 +0000

Before starting this blog. I would like you all to install two things in your computer from any browser:

Python from https://www.python.org/downloads/
VS code from https://code.visualstudio.com/download
PIP – Installed automatically with Python as part of python installation. You can check the PIP using the command: pip --version

Why do we need to install python?

Python (The Interpreter): Python is the brain behind the scenes. It reads your .py files and executes the code line by line.
Without Python installed, your computer won’t understand the instructions you write in Python code.

Why do we need VS Code (The Code Editor)?

Visual Studio Code (VS Code) is where you write your Python programs. It’s a powerful, lightweight text editor that makes writing code much easier with:

Syntax highlighting (colorful code)

Auto-complete suggestions

Debugging tools

Extensions (like Python formatter, linting, and more)

Understanding the execution of python program
The execution of python program involves two steps:

Compilation

Interpreter

Compilation
The process of converting a Python program into bytecode is known as compilation.

Bytecode consists of a fixed set of instructions that handle arithmetic, comparison, and memory operations. Since it is platform-independent, it can run on any operating system or hardware.
These bytecode instructions are stored in a .pyc file, which is usually created internally by Python. However, you can generate and view it explicitly using the commands:

python -m py_compile file_name.py
python -m dis file_name.py

Interpreter
The interpreter is responsible for converting Python bytecode (.pyc) into machine code (binary 0s and 1s) so that the CPU can execute the program.

It reads the bytecode and translates it into machine-level instructions.
This task is handled by the Python Virtual Machine (PVM), which ensures the program runs on the underlying hardware.

Here’s a simple diagram that illustrates the execution flow

To Summarize, When you write a Python program in a .py file, it’s in human-readable form. Once executed (using the command python file_name.py from terminal), Python compiles it into bytecode (.pyc), which is a lower-level set of instructions meant for the Python Virtual Machine (PVM). The PVM then translates this bytecode into machine code (binary instructions: 0s and 1s), which the computer’s CPU can directly understand and execute. At this stage, your program interacts with the hardware to perform tasks like displaying output, calculations, or saving files.

In the next blog, we’ll dive into Python keywords and built-in functions.

Thanks for reading! Catch you in the next one — happy learning! ❤️

Introduction to Python

Prakash Vinukonda — Sun, 06 Jul 2025 18:20:00 +0000

Hello Everyone,
My name is Prakash, and I'm excited to share my very first blog on python with you. My goal is simple - to make Python easy to understand, especially for beginners who prefer learning in plain, clear language with rich examples.

Let’s get started!

What is Python?

Python is a high-level programming language that allows us to communicate with computers by giving them a set of instructions to follow. In short, Python helps you tell a computer what to do, how to do it, and when to do it using easy-to-understand code.

Why Python?

Easy to Read Syntax

Versatility

Huge ecosystem of libraries and Frameworks

Cross-platform support (Windows, Mac, Linux)

What we can do with Python?

Domain	Build	Popular Tools
Web Development	Websites, APIs	Django, Flask, Streamlit, FastAPI
Data Analysis	Reports, Dashboards	Pandas, NumPy, Matplotlib
Machine Learning	Prediction Systems, AI Models	scikit-learn, TensorFlow, PyTorch
Automation	Task Automation, Web Scraping	Selenium, pyautogui, os
Data Engineering	Data Pipelines, ETL Jobs	PySpark, Airflow, SQLAlchemy
Game Development	2D Games	Pygame
App Development	Desktop/Mobile Apps (basic)	Kivy, BeeWare
Scientific Computing	Simulations, Equation Solving	SciPy, SymPy
DevOps & Testing	Auto Testing, Deployment Scripts	pytest, Ansible
Cybersecurity	Network Tools, Scanners	Scapy, Paramiko

A Short History of Python

Late 1980s: Guido van Rossum, a Dutch programmer, begins developing a new scripting language as a holiday project at the Centrum Wiskunde & Informatica (CWI) in the Netherlands.
Guido van Rossum

Key Milestones in Python

1991: Python’s first official version (0.9.0) is released. It included core features like functions, exceptions, and basic data types (lists, strings, etc.).
2000: Python 2.0 is launched, introducing features like list comprehensions and a garbage collection system.
2008: Python 3.0 is released - a major overhaul that is not backward compatible, but offers a cleaner and more consistent design.
2020: Support for Python 2 officially ends, encouraging everyone to migrate to Python 3.
2025: Python is one of the most widely used programming languages in the world

Who Uses Python Today?

Python is widely used by top companies like Google, Facebook, Netflix, and Amazon across industries such as tech, finance, healthcare, and gaming.
They use it for machine learning, automation, web development, data engineering, and backend systems in real-world, revenue-generating products.

Wrapping Up: Python is simple yet powerful — and as you've seen, it’s far from just a beginner’s tool. It’s trusted by some of the biggest names in tech to power real-world, high-impact applications. Whether you're automating tasks, analyzing data, or building web apps, Python has something for everyone.

On top of that, Python code is typically one-third to one-fifth the size of equivalent C++ or Java code - which means: Write less. Break less. Fix less.

In the next blog, we’ll explore what a program really is, how Python executes code step by step, and get familiar with concepts like the Python interpreter, compilation, and execution flow.

Thanks for reading! Catch you in the next one — happy learning! ❤️

DEV Community: Prakash Vinukonda

Python Behind the Scenes - Understanding Code Execution Flow

Introduction to Python