Introduction to Python

Python is a general-purpose programming language known for reading almost like plain English. It isn't tied to any one kind of task — the same language, and largely the same syntax, works whether you're automating a task, analyzing data, building a website, or training a machine learning model.

The first thing most people notice about Python's syntax: no curly braces, no semicolons. It uses indentation — the spacing at the start of a line — to mark where a block of code starts and ends. This isn't just a style choice; it's a real part of the language's syntax, and you'll look at it properly in the next lesson.

This section covers the language itself — the part that's identical no matter which of these you eventually do. Frameworks and libraries for any specific domain are a natural next step once you're comfortable here, not something to learn at the same time as the fundamentals.

Python is an interpreted language — you run a .py file directly, and Python reads and executes it line by line, rather than compiling it into a separate program first. This makes the write-and-run cycle fast, which is a big part of why Python is popular for quick scripts and experimentation.

Python has an unusually explicit set of design principles, half-jokingly called "the Zen of Python." Type this into any Python prompt and it prints all nineteen of them:

Two lines from it show up constantly in real Python code and discussions: "Simple is better than complex" and "There should be one — and preferably only one — obvious way to do it." Keep an eye out for both as this section goes on; they explain a lot of Python's specific design choices.

The next lesson gets Python actually running on your machine, so every example from here on is something you can try yourself.