Python Introduction

Python is a general-purpose programming language. “General-purpose” means you can build many types of software with it, not just one category.

Python is famous for one thing: readability. A beginner can read Python code and understand what it is doing, and a professional team can still use it to build real products.

What Python is (in simple terms)

When you write Python, you write instructions in a .py file. When you run the file, the Python interpreter reads your code and executes it line by line.

Python is an interpreted language in everyday usage (it runs through an interpreter), which makes it excellent for learning and for fast development.

Why companies use Python

Python is popular because it solves real problems efficiently:

• Web backends: build APIs and server logic
• Automation: scripts to rename files, scrape data, send emails
• Data and reporting: dashboards, ETL, analytics
• AI and machine learning: training models, building AI services
• Testing: automation tests and tools

How Python runs your code

When you run a program, this is the mental model:

1. You write instructions
2. Python reads them in order
3. Python executes them and produces output

flowchart LR
  A[Write code in .py] --> B[Run python file.py]
  B --> C[Python interpreter executes line by line]
  C --> D[Output / results]

Your first program (and what it means)

print("Hello, Python!")

• print() is a built-in function
• It displays text on the screen

Run:

python hello.py

Expected output:

Hello, Python!

The 3 beginner tools you will use most

• Terminal: to run Python files
• Editor (VS Code): to write code
• Browser: to search docs and learn

You do not need fancy setups at the beginning. You need a clean installation, consistent practice, and small projects.

How to think like a programmer from day 1

A strong concept that helps you learn faster:

• Programs are not magic
• A program is a set of instructions
• The computer follows instructions exactly
• If your output is wrong, the instructions are wrong or incomplete

Common confusion: Python vs Python packages

Python is the language.
Packages are add-ons (libraries) you install, like:

• requests (for HTTP)
• pandas (for data)
• numpy (for math)

You do not need packages to start learning. First, master core Python.

Quick learning checklist

By the end of the first 10 lessons, you should be able to:

• run Python from terminal
• use variables, strings, numbers
• use lists and dictionaries
• use if statements and loops
• write functions to reuse logic

In the next lesson, you will install Python correctly and verify the setup so your environment behaves consistently.