What is Python? The programming language, explained

Python is a free, general-purpose programming language: a way of writing instructions for a computer in text that people can read. It was designed to be short and clear, so a task that takes twenty lines in some languages often takes five in Python. People use it to automate chores, analyze data, build websites and train AI models. (This note is about the language, not the snake, though the name came from somewhere else entirely.)

In short

• Python is a programming language built for readability, and it is one of the most used languages in the world.
• Its strength is less the language itself than the huge collection of free, ready-made code that comes with it and around it.
• It trades raw speed for ease of writing, and leans on fast code written in other languages when speed matters.

What does Python code look like?

Here is a complete Python program. It adds up three prices and prints the total.

prices = [4.50, 12.00, 3.25]
total = sum(prices)
print(f"Total: {total:.2f}")

Read it line by line. The first line makes a list of three numbers and names it prices. The second line uses sum, a function Python comes with, to add them: 4.50 plus 12.00 plus 3.25 is 19.75, and the result is stored under the name total. The third line prints the words "Total: " followed by the number rounded to two decimal places, so the screen shows Total: 19.75.

Notice what isn't there. There are no type declarations saying "this is a decimal number", no semicolons, no curly braces, and no setup code around the three lines. Python uses indentation, the spaces at the start of a line, to show which lines belong together, so code is laid out the way people already lay out a list or an outline. The same program in Java or C needs a class or a main function, declared types and a formatting call, roughly three times as many lines.

Where did Python come from?

Python was created by Guido van Rossum, a Dutch programmer. In the language's official FAQ he recalls starting it during the 1989 Christmas holidays, and posting the first version to the USENET discussion groups in February 1991. He was reading scripts of Monty Python's Flying Circus, the 1970s BBC comedy, at the time, and wanted a name that was "short, unique, and slightly mysterious". Python has been open source from the start, and since 2001 it has been looked after by the nonprofit Python Software Foundation.

The language's biggest break came with Python 3, released in December 2008, which fixed old design mistakes at the cost of not running some older code unchanged. The move took the community more than a decade: Python 2 reached its end of life on 1 January 2020. New versions now arrive every October, and each is supported for about five years. According to the Python developer guide, Python 3.15 was released on 9 October 2026.

Why do beginners and scientists both like it?

Beginners like Python because it lets them think about the problem rather than the punctuation. It is interpreted, which means a program called the interpreter reads the code and runs it straight away, with no separate build step. You can type a line, press Enter and see the answer, which makes it easy to experiment.

Scientists and analysts like it for a different reason: the libraries. A library is a package of code someone else has written and shared. Python comes with a large standard library for files, dates, web requests, email and much more, which its makers call "batteries included". Beyond that, the Python Package Index, PyPI, listed more than 930,000 projects in November 2026, according to its home page. One command downloads any of them.

A few of those libraries define whole fields. NumPy handles large arrays of numbers. pandas handles tables of data, like a spreadsheet you control with code. Matplotlib draws charts. PyTorch and TensorFlow train neural networks. Much of machine learning is written in Python for this reason, and the AI boom has pulled more people toward it: in the 2025 Stack Overflow Developer Survey, 57.9% of respondents said they had used Python in the past year, up 7 percentage points from 2024.

What do people build with Python?

• Automation: renaming a thousand files, filling in forms, pulling numbers out of reports every morning.
• Data analysis: cleaning messy data, running statistics, making charts for a report or a paper.
• AI and machine learning: training models, and calling AI services through an API from a few lines of code.
• Websites and web services: the server side of sites, built with frameworks such as Django and Flask, which answer requests that travel over the internet.
• Science and engineering: simulations in physics, biology and astronomy, and the glue between lab instruments and analysis.

What Python is used for less often says as much. It isn't the usual choice for code that runs inside a web browser (JavaScript is), for phone apps (Swift and Kotlin are), or for games and operating systems where every millisecond counts (C and C++ are).

How does Python compare with other languages?

Every language makes trade-offs. Python's is ease of writing over speed of running. This table sets it beside two languages people often weigh it against.

	Python	JavaScript	C
How it runs	Read and run by an interpreter	Run by a browser or by Node.js	Compiled into machine code first
Types	Worked out while running	Worked out while running	Declared in the code
Typical speed	Slow for pure loops	Fast, thanks to modern engines	Among the fastest
Best known for	Data, AI, scripts, back ends	Web pages, web apps	Operating systems, devices
First released	1991	1995	1972

A common misconception is that a slow language must be a toy. In practice, the heavy work in Python's science libraries is done by code written in C, C++ or Fortran, and Python is the readable layer that tells that fast code what to do. A data scientist writes one Python line; underneath, compiled code crunches millions of numbers. Where Python's speed does bite is in long loops of plain Python code, and that is one reason recent versions have worked on running code faster and on using several processor cores at once.

How do people start learning Python?

Python is free to download from python.org, and it comes preinstalled on many systems. The official Python tutorial walks through the language from the first line. Many people now also learn by asking an AI assistant to write a small script and then reading what it wrote, which is close to vibe coding; it works best when you can read the result well enough to spot a mistake.

Learning Python also teaches what any language does underneath: storing values in memory, repeating steps, making decisions. Those ideas carry over to every other language, and to understanding how computers work at all.

Check yourself

• Without looking back: what does each of the three lines in the prices example do?
• Why can a "slow" language like Python still run fast data analysis?
• What is a library, and why do Python's libraries matter more than its syntax?

Sources

• General Python FAQ — Python Software Foundation
• Status of Python versions — Python Developer's Guide, Python Software Foundation
• The Python Tutorial — Python Software Foundation
• The Python Package Index — Python Software Foundation, November 2026
• 2025 Developer Survey: Technology — Stack Overflow, 2025