De Morgan's Laws

De Morgan's laws describe how to transform negations of compound Boolean expressions. These laws, named after mathematician Augustus De Morgan, are fundamental to Boolean algebra and appear frequently in interview questions and code simplification. Understanding these transformations helps you simplify complex negations and write more readable conditions. The Two Laws De Morgan's laws state that negating an "and" flips it to "or" (and vice versa), while also negating each operand: Practical Applications De Morgan's laws help simplify negated conditions, making them easier to understand: Simplifying Validation De Morgan's laws are especially useful when inverting validation conditions: Memorize these two transformations. They come up constantly when simplifying negated conditions in validat

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This section is part of the Control Flow: Advanced 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.

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