Variables and Assignment

Concepts covered: pyVariables

Variables are the foundation of any Python program. They let you store, reference, and manipulate data throughout your code. Creating Variables In Python, you create a variable by assigning a value to a name using the equals sign. Python automatically determines the data type based on the value you provide. Each variable stores a different type of data. Python figures out the type automatically, so you never need to declare it explicitly. Python itself has an origin story that surprises most people. Variable names in Python are case-sensitive. The names count, Count, and COUNT all refer to three completely different variables. Python naming conventions recommend lowercase with underscores for variable names, a style known as snake_case that distinguishes Python from languages that use came

About This Interactive Section

This section is part of the Python Foundations: Beginner lesson on DataDriven, a free data engineering interview prep platform. Each section includes explanations, worked examples, and hands-on code challenges that execute in real time. SQL queries run against a live PostgreSQL database. Python runs in a sandboxed Docker container. Data modeling problems validate against interactive schema canvases. All content is framed around what data engineering interviewers actually test at companies like Meta, Google, Amazon, Netflix, Stripe, and Databricks.

How DataDriven Lessons Work

DataDriven combines four interview rounds (SQL, Python, Data Modeling, Pipeline Architecture) with adaptive difficulty and spaced repetition. Easy problems get harder as you improve. Weak concepts resurface until you master them. Your readiness score tracks progress across every topic interviewers test. Every lesson section ends with problems you solve by writing and running real code, not by picking multiple-choice answers.