Conditional Assignment

Conditional assignment lets you assign a value to a variable based on a condition, all in a single line. This is also called a ternary expression or conditional expression. It makes your code more concise when you need to choose between two values. Ternary Expression Syntax Using in Function Calls Conditional expressions are especially useful when passing arguments to functions or building strings: Nested Conditionals You can nest conditional expressions, but this quickly becomes hard to read. Use with caution: Ternary expressions are powerful but easy to misuse. Follow these guidelines to keep your conditional assignments readable: Default Values with or Ternary expressions work best for straightforward two-option assignments. When the condition or either value is long, split the expressi

About This Interactive Section

This section is part of the Control Flow: Intermediate 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.